The venous duct is denied. Basic research. On what ultrasound can a doctor determine the sex of a child

26.06.2020

FETAL CIRCULATION

Fetal circulation is otherwise called placental circulation: in the placenta, there is an exchange of substances between the blood of the fetus and maternal blood (while the blood of the mother and fetus does not mix). In the placenta, placenta, begins with its roots umbilical vein, v. umbilicalis through which arterial blood oxidized in the placenta is directed to the fetus. Following in the composition of the umbilical cord (umbilical cord), funiculus umbilicalis, to the fetus, the umbilical vein enters through the umbilical ring, anulus umbilicalis, into the abdominal cavity, goes to the liver, where part of the blood through venous duct, Arantyev (ductus venosus) dumped in inferior vena cava, v. cava inferior where it mixes with venous blood ( 1 mixing ), and the other part of the blood passes through the liver and through the hepatic veins also flows into the inferior vena cava ( 2 mixing ). Blood through the inferior vena cava enters the right atrium, where its main mass, through the valve of the inferior vena cava, valvula venae cavae inferioris, passes through oval hole, foramen ovale, interatrial septum into the left atrium. From here it follows to the left ventricle, and then to the aorta, along the branches of which it goes primarily to the heart, neck, head and upper limbs. In the right atrium, except for the inferior vena cava, v. cava inferior, brings venous blood to the superior vena cava, v. cava superior, and the coronary sinus of the heart, sinus coronarius cordis. Venous blood entering the right atrium from the last two vessels is sent along with a small amount of mixed blood from the inferior vena cava to the right ventricle, and from there to the pulmonary trunk, truncus pulmonalis. It flows into the aortic arch, below the place where the left subclavian artery originates from it. ductus arteriosus, ductus arteriosus (Botallov duct), through which blood from the latter flows into the aorta. From the pulmonary trunk, blood enters the lungs through the pulmonary arteries, and its excess through the arterial duct, ductus arteriosus, is sent to the descending aorta. Thus, below the confluence of the ductus arteriosus, the aorta contains mixed blood ( 3 mixing ), entering it from the left ventricle, rich in arterial blood, and blood from the arterial duct with a high content of venous blood. Through the branches of the thoracic and abdominal aorta, this mixed blood is directed to the walls and organs of the chest and abdominal cavities, the pelvis, and to the lower extremities. Part of the indicated blood follows two - right and left - umbilical arteries, a.a. umbilicales dextra et sinistra , which, located on both sides of the bladder, exit the abdominal cavity through the umbilical ring and, as part of the umbilical cord, funiculus umbilicalis, reach the placenta. In the placenta, the fetal blood receives nutrients, gives off carbon dioxide and, enriched with oxygen, is again directed through the umbilical vein to the fetus. After birth, when the pulmonary circulation begins to function and the umbilical cord is tied up, the umbilical vein, venous and arterial ducts, and distal umbilical arteries gradually become empty; all these formations are obliterated and form ligaments.

umbilical vein, v. umbilicalis , forms round ligament of the liver lig. teres hepatis; venous duct, ductus venosus - venous ligament, lig. venosum; ductus arteriosus, ductus arteriosus - arterial ligament, lig. arteriosum, and from both umbilical arteries, a.a. umbilicales , strands are formed, medial umbilical cords, lig g . umbilicalia medialia , which are located on the inner surface of the anterior abdominal wall. Overgrows also oval hole, foramen ovale , which turns into oval fossa, Fossa ovalis , and the valve of the inferior vena cava, valvula v. cavae inferioris, which lost its functional significance after birth, forms a small fold stretched from the mouth of the inferior vena cava towards the oval fossa.

Fig.113. Fetal circulation

1 - placenta (placenta); 2 - umbilical vein (v. umbilicalis); 3 - portal vein (v. portae); 4 - venous duct (ductus venosus); 5 - hepatic veins (vv. hepaticae); 6 - oval hole (foramen ovale); 7 - arterial duct (ductus arteriosus); 8 - umbilical arteries (aa. umbilicales)

(ductus venosus, PNA, JNA)
see Ductus venosus.

Watch value Venous duct in other dictionaries

Venous- venous, venous (anat.). App. to the vein. Deoxygenated blood.
Explanatory Dictionary of Ushakov

Duct- see leak and grind.
Dahl's Explanatory Dictionary

Venous App.- 1. Corresponding in value. with noun: a vein associated with it. 2. Peculiar to a vein, characteristic of it.
Explanatory Dictionary of Efremova

flow M.- 1. A branch of the river, a stream connecting two reservoirs. 2. Narrow connecting cavity, canal (in the body).
Explanatory Dictionary of Efremova

Venous- see Vienna.
Explanatory Dictionary of Kuznetsov

Duct- -a; m.
1. Branch of the river; a stream, a river that connects two bodies of water. The lakes are connected by a deep channel. In the lower reaches, the river breaks into many channels.
2. Anat. Narrow........
Explanatory Dictionary of Kuznetsov

allantoid duct- (du tus allantoicus, LNE) a canal lined with epithelium connecting the cavity of the hindgut with the cavity of allantois; in the human embryo, A. p. is reduced.
Big Medical Dictionary

Anastomosis Venous- (a. venosa) A., connecting two venous vessels.
Big Medical Dictionary

Arantsiev Protok- (G. C. Aranzi, 1530-1589, Italian anatomist and surgeon) see List of anat. terms.
Big Medical Dictionary

arterial duct- (ductus arteriosus, PNA; ductus arteriosus (Botalli), BNA; syn. Botallov proto) a blood vessel connecting the pulmonary trunk of the fetus with the aorta; formed from the left sixth (aortic) branchial ........
Big Medical Dictionary

Bartholin duct- (S. Bartholin, 1655-1738, Danish anatomist) see Large sublingual duct.
Big Medical Dictionary

Botallov Protok- (ductus arteriosus (Botalli), BNA; L. Botallo, 1530-1600, Italian surgeon and anatomist) see Arterial duct.
Big Medical Dictionary

Vartonov Protok- (ductus Whartonianus; Th. Wharton, 1614-1673, English anatomist) see Submandibular duct.
Big Medical Dictionary

Venous Return- indicator of blood circulation: volumetric blood flow velocity in the right atrium; Normally, it strictly corresponds to the minute volume of the heart.
Big Medical Dictionary

Venous Return Cardiotomy- a sharply increased venous return observed after some heart operations (pericardectomy, mitral commissurotomy, etc.).
Big Medical Dictionary

Venous Return Coronary- indicator of coronary circulation: volumetric blood flow velocity in the coronary sinus; normally equal to 50-80% of the volumetric blood flow velocity in the coronary arteries.
Big Medical Dictionary

Venous Congestion- (stasis venosa) see Venous hyperemia.
Big Medical Dictionary

Venous duct- (ductus venosus, PNA, JNA) see the list of anat. terms.
Big Medical Dictionary

Venous Sinus Sclera- (sinus venosus sclerae, PNA, BNA, JNA; synonym: venous sinus of the sclera, Lautov canal, scleral canal, Schlemm canal) a circular venous vessel located in the thickness of the sclera on the border with ........
Big Medical Dictionary

Venous Angle- (angulus venosus; synonym Pirogov venous angle) the confluence of the subclavian and internal jugular veins, forming the brachiocephalic vein.
Big Medical Dictionary

Virzungov Protok- (ductus Wirsungianus; J. G. Wirsung, 1600-1643, German anatomist) see Pancreatic duct.
Big Medical Dictionary

Volfov Protok- (ductus Wolffi; C. F. Wolff, 1733-1794, morphologist) see Primary kidney duct.
Big Medical Dictionary

Hensen's duct- (V. Hensen) see Connecting duct.
Big Medical Dictionary

hepatopancreatic duct- (ductus hepatopancreaticus, LNE; hepato- + Greek pankteas, pancreatos pancreas) section of the embryonic common bile duct from the confluence of the ventral anlage duct into it ........
Big Medical Dictionary

thoracic duct- (ductus thoracicus, PNA, BNA, JNA) a lymphatic vessel through which the lymph flows into the venous bed from the legs, pelvis, walls and organs of the abdominal cavity, left arm, left half of the chest, ........
Big Medical Dictionary

Vitelline intestinal duct- see Yolk duct.
Big Medical Dictionary

Yolk duct- (ductus vitellinus, LNE; synonym: yolk-intestinal duct, umbilical-intestinal duct) canal in the yolk stalk, lined with endodermal epithelium, connecting the cavity of the middle ........
Big Medical Dictionary

bile duct- (ductus choledochus) - common bile duct.
Big Medical Dictionary

Bile Duct Common- (ductus choledochus, PNA, BNA, JNA; syn. bile duct) extrahepatic Zh. p., formed by the connection of the hepatic and cystic ducts; opens on the major duodenal papilla.
Big Medical Dictionary

female duct- see Paramesonephric duct.
Big Medical Dictionary

Dopplerography was used to study the quantitative indicators of blood flow velocity in the venous duct of the fetus in various phases of the cardiac cycle in healthy women with 11 to 14 weeks of pregnancy. At the same time, the concentration in the blood of a pregnant woman associated with pregnancy plasma protein A (PAPP-A) and the free beta subunit of chorionic gonadotropin (beta-CG) was taken into account. It was found that in healthy pregnant women, the linear blood flow velocities in the venous duct of the fetus have a significant (almost twofold) variation range, which excludes the dependence of these indicators on the duration of pregnancy in weeks and on the thickness of the chorion. A weak negative correlation was established between the content of specific proteins and hormones of pregnancy (PAPP-A and beta-CG) in the blood of a woman and the relative angle-independent parameters of blood flow in the fetal venous duct - the ratio of blood flow rates in systole and early diastole, as well as the vein velocity index and the index vein resistance. The revealed dependence gives grounds to use the angle-independent parameters of the blood flow velocity curves in the venous duct of the fetus, determined at the turn of the first and second trimesters of pregnancy, as an additional criterion for predicting prenatal risk.

pregnancy

dopplerography

venous duct of the fetus

flow velocity curves

1. Altynnik N.A. The value of the Doppler assessment of blood flow in the venous duct of the fetus in early pregnancy for the formation of a high-risk group for the birth of children with chromosomal abnormalities. Vestnik Volgogradskogo med. university. - 2012. - No. 4. - P. 66–68.

2. Lisyutkina E.V. Diagnostic value of dopplerography of blood flow in the venous duct of the fetus at different stages of pregnancy: author. dis. ... cand. honey. Sciences. - M., 2013. - 18 p.

3. The procedure for providing medical care in the field of "obstetrics and gynecology (with the exception of the use of assisted reproductive technologies)". Order of the Ministry of Health of the Russian Federation dated November 01, 2012 No. 572n.

4. Radzinsky V.E. obstetric aggression. - M.: Publishing house of the journal Status Praesens, 2011. - 618 p.

5. ISUOG Practice Guidelines: Use of Doppler Ultrasound Technology in Obstetrics. International Society for Ultrasound Diagnostics in Obstetrics and Gynecology (ISUOG) / A. Bride, G. Acharya, C. M. Bilardo et al. // Ultrasonic and functional diagnostics. - 2014. - No. 5. - P. 87–98.

6. Maiz N. Ductus venosus Doppler at 11 to 13 weeks of gestation in the prediction of outcome in twin pregnancies / N. Maiz, I. Staboulidou, A.M. Leal et al. // obstet. Gynecol. - 2009. - Vol. 113. - R. 860-865.

The relevance of the problem of early prediction and prevention of the development of obstetric complications in order to reduce perinatal and infant morbidity and mortality determines the search for new predictors of problematic outcomes of pregnancy and childbirth. Over the past decade, medical institutions everywhere have been equipped with ultrasound scanners equipped with color Doppler mapping and reducing the total radiation exposure to the fetus to a safe threshold. This makes it possible to expand the scope of the standard screening ultrasound examination of pregnant women for the early formation of high-risk groups. Among the Dopplerographic parameters determined in the first trimester of pregnancy, the study of blood flow velocity curves (BFRs) in the venous duct of the fetus attracted the greatest attention of researchers. The high prognostic value of studying the CSC spectrum in this vessel at the end of the first - beginning of the second trimester of pregnancy has been proven in relation to the presence of chromosomal abnormalities, congenital heart defects in the fetus and the outcome of multiple pregnancy. But these studies concerned only the qualitative study of CSCs (registration of retrograde or unidirectional blood flow). Quantitative normative parameters of blood flow velocity in the fetal venous duct at the turn of the first and second trimesters of pregnancy in various phases of the cardiac cycle remain unknown to date. This limits the possibility of using this method to predict other types of obstetric pathology. The existing problem marked the direction of the study.

The purpose of the work is to determine the normative parameters of fetal blood flow rates at 11-14 weeks of pregnancy.

Material and research methods

The object of the study was 72 somatically healthy women with a physiological course of a singleton pregnancy, having from 11 weeks. + 0/7 days to 13 weeks + 6/7 days of gestation. Criteria for inclusion in the study:

a) age from 18 to 35 years;

b) pregnancy from 11 to 14 weeks;

c) bearing one fetus;

d) the location of the chorion in the bottom or along the side walls of the uterus;

e) the absence of extragenital pathology in the stage of sub- and decompensation;

e) spontaneous conception;

g) the absence of an episode of threatening termination of the observed pregnancy both at the time of the study and at its earlier stages.

The study of blood circulation in the venous duct of the fetus was carried out on an ultrasound device Voluson E8 (USA), in compliance with the ALARA (As Low As Reasonably Achieveble) principle - “As Low As Reasonably Achievable”, i.e. using the most prudently low output power. Registration of blood flow in the venous duct of the fetus was carried out by specialists with the appropriate Certificate of the Fetal Medicine Foundation. The blood flow velocity was measured in systole (S), diastole (E) of the heart ventricles, as well as during contraction of the vestibules of the heart, i.e. in late diastole (A).

The ratios of the phase velocities of the blood flow (S/E and S/A) were calculated, as well as the angle-independent indices - the vein resistance index (RII) and the vein velocity index (VRI). The study was conducted as an addition to the standard examination in the first trimester of pregnancy, determined by the "Basic range of examination of pregnant women" of the federal Procedure for the provision of medical care in the profile "obstetrics and gynecology (excluding the use of assisted reproductive technologies)" . In addition to the data of the clinical examination of patients, the work took into account the content in the blood of women on the day of the examination of pregnancy-associated plasma protein A (PAPP-A) and the free beta subunit of chorionic gonadotropin (beta-CG), both in quantitative values and in the form of "multiple of median" (MoM).

The recorded data were processed by the method of correlation and variance analysis and are presented as "mean ± standard deviation" (M ± SD) and 95% confidence interval (95% CI).

Research results and discussion

The data obtained indicate that the rate of blood flow in the venous duct in the fetus at the turn of the first and second trimesters of gestation during physiological pregnancy varies widely (table).

In different phases of the fetal cardiac cycle, individual characteristics in the group of subjects determined more than a twofold discrepancy between the recorded indicators. At the same time, the linear parameters of blood circulation did not depend either on the gestational age in weeks or on the thickness of the chorion measured by ultrasound scanning. There were no cases of retrograde blood flow in the venous duct in the fetus (a marker of intrauterine hypoxia or hereditary pathology) in the examined women.

Indicators of blood flow velocity curves in the venous duct of the fetus in different phases of the cardiac cycle in the early stages of physiological pregnancy

The ratios of blood flow rates in systole and early diastole (S/E) in healthy pregnant women were less variable - the discrepancies in the indicators were no more than 11%. This made it possible to reveal a weak inverse correlation between this indicator and the concentration of chorionic gonadotropin in the blood of a pregnant woman (r = -0.3; p< 0,05). Соотношение скоростей кровотока в венозном протоке плода в систолу и позднюю диастолу (S/А) также имело большую вариабельность (почти двухкратное превышение максимального значения над минимальным), что не позволило определить взаимосвязь этого показателя с другими результатами стандартного обследования беременных. Размах вариации индексов скоростей вен и резистентности вен был намного меньше - в пределах 46 и 37 % соответственно. Это определило наличие отрицательной корреляционной связи между сравниваемыми параметрами кровотока в венозном протоке плода и продукцией специфических гормонов и белков беременности - бета-ХГ и РАРР-а (коэффициенты корреляции соответственно равны - 0,41 (р < 0,05) и - 0,34 (р < 0,05). При этом не имел преимуществ вид представления бета-ХГ и РАРР-а (количественные значения или МоМ); связь указанных параметров была слабой, но доказанной посредством проверки нулевой гипотезы. Так как определение продукции бета-ХГ и РАРР-а в МоМ используется в качестве одного из критериев прогноза пренатального риска с ранних сроков беременности , выявленная взаимосвязь открывает перспективы использования для этих целей и числовых значений исследования кровотока в венозном протоке плода. Но оценка эффективности нового прогностического критерия становится возможной только при условии четкого представления о нормативных значениях КСК в указанном кровеносном сосуде.

Conclusion

The data obtained are preliminary, however, they show that the curves of blood flow velocities in the venous duct of the fetus in early pregnancy can be subjected not only to a qualitative analysis (detection of retrograde and zero blood flow), but can also be presented as numerical values for early prediction gestational complications.

Reviewers:

Agarkova L.A., Doctor of Medical Sciences, Professor, Director, Research Institute of Obstetrics, Gynecology and Perinatology, Siberian Branch of the Russian Academy of Medical Sciences, Tomsk;

Sotnikova L.S., Doctor of Medical Sciences, Professor of the Department of Obstetrics and Gynecology of the FPC and PPS, Siberian State Medical University of the Ministry of Health of the Russian Federation, Tomsk.

The work was received by the editors on February 12, 2015.

Bibliographic link

Mikheenko G.A., Yuriev S.Yu., Korotkova Yu.Yu. PHASE PARAMETERS OF BLOOD FLOW VELOCITY IN THE FETUS VENOUS DUCT IN HEALTHY WOMEN AT 11–14 WEEKS OF PREGNANCY // Fundamental Research. - 2015. - No. 1-1. - S. 107-109;
URL: http://fundamental-research.ru/ru/article/view?id=36777 (date of access: 12/13/2019). We bring to your attention the journals published by the publishing house "Academy of Natural History"

Screening of the 1st (first) trimester. Screening times. Screening results. ultrasound screening.

Your baby has overcome all the difficulties and dangers associated with the embryonic period. He safely got through the fallopian tubes to the uterine cavity, there was an invasion of the trophoblast into the endometrium, the formation of the chorion. The embryo grew and changed incredibly every week, the rudiments of all the most important organs and systems were formed, the torso, head, and limbs were formed.
Finally grown to 10 weeks, acquiring all the necessary traits, a child-like configuration, which allowed him to be called a fetus from that moment on.
The time has come for the screening of the 1st (first) trimester.
Today we will talk about the timing of the screening of the first trimester, the results of ultrasound screening.

This topic is vast and one article here certainly will not get off. We have to analyze a lot of anomalies and malformations that can already be suspected or even diagnosed at this time. But let's start from the beginning.

What is screening?

Screening- this is a set of necessary measures and medical studies, tests and other procedures aimed at the preliminary identification of persons among whom the probability of having a certain disease is higher than in the rest of the population under study. Screening is only the initial, preliminary stage of the examination of the population, and individuals with positive screening results need a subsequent diagnostic examination to establish or exclude the presence of a pathological process. The impossibility of performing diagnostic tests to establish or exclude the presence of a pathological process with a positive screening result makes the screening itself pointless. For example, carrying out biochemical screening of fetal chromosomal diseases is not justified if subsequent prenatal karyotyping is not possible in this region.

Any screening program must be accompanied by sound planning and quality assessment of screening, as any screening test performed in the general population may do more harm than good to the individuals being examined. The concept of “screening” has fundamental ethical differences from the concept of “diagnosis”, since screening tests are carried out among potentially healthy people, so it is very important that they have a realistic understanding of the information that this screening program provides. For example, when performing ultrasound screening of fetal chromosomal pathology in the first trimester of pregnancy, women should not get the idea that the detection of an increase in the thickness of the collar space (NTP) in the fetus necessarily indicates the presence of Down's disease and requires termination of pregnancy. Any screening has certain limitations, in particular, a negative screening test result does not guarantee the absence of a disease, just as a positive test result does not indicate its presence.

When and why was first trimester screening invented?

Every woman has a certain risk that her child may have a chromosomal pathology. It is for everyone, and it doesn’t matter what lifestyle she leads and social status she occupies.
In systematic (non-sampling) screening, a specific screening test is offered to all individuals in a specific population. An example of such screening is ultrasound screening of fetal chromosomal abnormalities in the first trimester of pregnancy, which is offered to all pregnant women without exception for a period of 11-13 (+6) weeks.

So, first trimester screening- this is a set of medical studies conducted at a period of 11-13 (+6) weeks, and aimed at the preliminary identification of pregnant women, among whom the probability of having a child with chromosomal abnormalities (CA) is higher than in other pregnant women.

The main place among the detected CA is occupied by Down syndrome (trisomy of 21 pairs of chromosomes).
The English physician John Langdon Down was the first to describe and characterize the syndrome, later named after him, in 1862, as a form of mental disorder.
Down syndrome is not a rare pathology - on average, there is one case in 700 births. Until the middle of the 20th century, the causes of Down syndrome remained unknown, but the relationship between the likelihood of having a child with Down syndrome and the age of the mother was known, and it was also known that all races were affected by the syndrome. In 1959, Jerome Lejeune discovered that Down syndrome is due to trisomy of the 21st pair of chromosomes, i.e. the karyotype is represented by 47 chromosomes instead of the normal 46, since the chromosomes of the 21st pair, instead of the normal two, are represented by three copies.

In 1970, the first screening method for trisomy 21 in a fetus was proposed, based on an increase in the likelihood of this pathology with an increase in the age of a pregnant woman.
In screening based on maternal age, only 5% of women will fall into the “high risk” group, and this group will include only 30% of fetuses with trisomy 21 from the entire population.
In the late 1980s, screening methods appeared that take into account not only age, but also the results of a study of the concentration of such biochemical products of fetal and placental origin in the blood of a pregnant woman as alpha-fetoprotein (AFP), unconjugated estriol (uE3), human chorionic gonadotropin (hCG ) and inhibin A. This screening method is more effective than screening only for the age of the pregnant woman, and with the same frequency of invasive interventions (about 5%), it can detect 50-70% of fetuses with trisomy 21.
In the 1990s, a screening method was proposed based on the age of the mother and the value of NT (thickness of the collar space) of the fetus at 11–13 (+6) weeks of pregnancy. This screening method can detect up to 75% of fetuses with a chromosomal pathology with a false positive rate of 5%. Subsequently, the screening method, based on the age of the mother and the value of fetal TB at 11–13 (+6) weeks of pregnancy, was supplemented by determining the concentrations of biochemical markers (free fraction of β-hCG and PAPP-A) in the mother's blood serum in the first trimester of pregnancy, which made it possible to identify 85–90% of fetuses with trisomy 21.
In 2001, it was found that 60–70% of fetuses with trisomy 21 and 2% of fetuses with a normal karyotype did not visualize the nasal bones on ultrasound at 11–13 weeks. The inclusion of this marker in the screening method based on ultrasound and the determination of biochemical markers in the first trimester of pregnancy can increase the frequency of detection of trisomy 21 up to 95%.

What US - markers that increase the risk of CA, we evaluate?

First of all, this is the expansion of the thickness of the collar space (NTP), the lack of visualization of the nasal bones, the reverse flow of blood in the venous duct and tricuspid regurgitation.

Collar space- is an ultrasound manifestation of the accumulation of fluid under the skin in the back of the neck of the fetus in the first trimester of pregnancy.

The term "space" is used regardless of whether this space has partitions or not, whether this space is localized in the neck or extends to the entire body of the fetus.
The frequency of occurrence of chromosomal diseases and malformations in the fetus depends on the size of the TVP, and not on its ultrasonic characteristics.
In the second trimester of pregnancy, the nuchal space usually disappears or, in rare cases, transforms into either cervical edema or cystic hygroma, with or without generalized fetal edema.

The thickness of the nuchal space of the fetus can be measured during transabdominal ultrasound in 95% of cases, in other cases a transvaginal examination is necessary. At the same time, the results obtained during a transabdominal or transvaginal study do not differ.
1 Measurements are made at 11–13 (+6) weeks of pregnancy with a coccyx-parietal size of the fetus from 45 mm to 84 mm. This is an important point, because it is not uncommon for a period of exactly 11 weeks or 11 weeks and 1-2 days the fetus is a couple of millimeters less than 45 mm. This is a variant of the norm, but the study in this case will have to be postponed for a week.
2 The measurement must be taken strictly in the sagittal section of the fetus, with the head of the fetus in a neutral position.
3 The image should be magnified so that only the fetal head and upper chest are visible on the screen.
4 The size of the image should be increased so that the minimum cursor offset results in a size change of 0.1 mm.
5 The thickness of the collar space should be measured at its widest point. It is necessary to differentiate the echostructure of the skin of the fetus and the amniotic membrane.
6 Cursors should be set on the inner boundaries of the echo-positive lines that delimit the collar space without going into it.
7 During the study, it is necessary to measure the TVP several times and choose the maximum of the measurements obtained.
In 5-10% of cases, the umbilical cord is wrapped around the neck, which can lead to a false increase in TVP. In such cases, TVP should be measured on both sides of the umbilical cord, and the average of these two measurements is used to assess the risk of fetal chromosomal abnormality.

Visualization of the nasal bones of the fetus

Should be carried out at 11-13 (+6) weeks of gestation and with a fetal CTE of 45-84 mm.
It is necessary to enlarge the image of the fetus so that only the head and upper body of the fetus are shown on the screen.
A strictly sagittal section of the fetus should be obtained, and the plane of insonation should be parallel to the plane of the nasal bone.
When visualizing the nasal bone, three separate lines should be present. The upper line represents the skin of the fetal nose, the lower, more echogenic and thicker, represents the nasal bone. The third line is a continuation of the first, but is slightly higher than it and represents the tip of the fetal nose.
At 11–13(+6) weeks, a fetal profile can be obtained and evaluated in more than 95% of fetuses.
With a normal karyotype, the absence of visualization of the nasal bones is typical for 1% of fetuses in European women and 10% of fetuses in Afro-Caribbean women.
Nasal bones are not visualized in 60–70% of fetuses with trisomy 21, 50% of fetuses with trisomy 18, and 30% of fetuses with trisomy 13.
With a false-positive rate of 5%, combined screening including measurement of TST, imaging of the fetal nasal bones, and measurement of maternal serum PAPP-A and β-hCG has the potential to detect more than 95% of fetuses with trisomy 21.

This fetus is one of the dichorionic twins. TVP and blood flow in the venous duct are normal, but there is no visualization of the nasal bones. The result of karyotyping is Down syndrome, the karyotype of the 2nd fetus from twins is normal.

Doppler venous duct and tricuspid regurgitation

With chromosomal abnormalities, malformations of various organs and systems are often formed, including congenital malformations of the cardiovascular system.

The venous duct is a unique shunt that delivers oxygenated blood from the umbilical vein, which is directed primarily through the foramen ovale to the left atrium, to the coronary and cerebral arteries. The blood flow in the ductus venosus has a characteristic shape with a high velocity in the phase of ventricular systole (S-wave) and diastole (D-wave) and orthograde blood flow in the phase of atrial contraction (a-wave).
At 11–13(+6) weeks of pregnancy, impaired blood flow in the venous duct is combined with the presence of chromosomal pathology or heart defects in the fetus and is a sign of a possible adverse pregnancy outcome. At this gestational age, the pathological form of blood flow velocity curves is observed in 80% of fetuses with trisomy 21 and in 5% of fetuses with a normal karyotype.
Tricuspid regurgitation is a wave of backflow of blood through the valve between the right ventricle and the atrium of the heart. In 95% of cases, tricuspid regurgitation, as well as reverse blood flow in the venous duct, disappears over the next few weeks, usually by 16 weeks; however, in 5% of cases it may indicate the presence of congenital heart disease. In this connection, it is recommended to undergo an extended fetal echocardiography at 18-20 weeks.

It is extremely important and necessary that specialists involved in calculating the risk of fetal chromosomal pathology based on an assessment of its profile undergo appropriate training and certification confirming the level of quality in performing this type of ultrasound examination.

Of course, screening of the first trimester is not limited to the determination of ultrasound markers that increase the risk of having a child with chromosomal abnormalities such as Down Syndrome, Edwards Syndrome, Patau Syndrome, Turner Syndrome and Triploidy. In this period, developmental anomalies such as exencephaly and acrania, malformations of the limbs and sirenomelia, omphalocele and gastroschisis, megacystis and s-m prune belly, anomaly of the body stem can also be diagnosed, suspect s-m Dandy-Walker and Spina bifida when changing sizes of the IV ventricle, anorectal atresia upon detection of pelvic translucency (pelvic translucency). And that's not all. I will try in the future to talk about the listed anomalies and malformations.

In conclusion, a few words about the procedure for screening the first trimester in our center

All specialists of our center work according to the recommendations of the international organization The Fetal Medicine Foundation (https://www.fetalmedicine.org/) and have certificates from this organization. The Fetal Medicine Foundation (FMF), headed by Professor Kypros Nikolaides, is engaged in research in the field of fetal medicine, the diagnosis of fetal anomalies, the diagnosis and treatment of various complications of pregnancy. Certified specialists and centers receive FMF-developed software for calculating the risk of fetal chromosomal pathology according to ultrasound and biochemical screening. To obtain a certificate in ultrasound examination at 11-13 (+6) weeks, it is necessary to complete theoretical training on an FMF-supported course; take a practical training in an FMF-accredited center; provide FMF with ultrasound photographs demonstrating the measurement of fetal TP, visualization of the bones of the nose, Doppler flow in the venous duct and tricuspid valve according to the criteria developed by FMF.

After filling out and signing numerous documents and consents at the registry, you will be invited to the ultrasound room, where I or my colleagues will assess the development of the fetus, all the necessary ultrasound markers of CA, as well as other possible changes in the chorion, uterine walls and ovaries.
After the examination, you will be given a conclusion in two copies and photographs of your baby (or babies). You keep one copy of the conclusion with you, and the second will need to be given in the treatment room, where blood will be taken from your vein for the biochemical part of the screening. Based on ultrasound and biochemistry data, special software will calculate the individual risk of fetal chromosomal pathology and in 1-2 days you will receive a result indicating individual risks for the main CA. If you wish, the result can be received by e-mail.
If you get results with a low risk of major CA, you will be advised to repeat the ultrasound at 19-21 weeks of pregnancy. If the risk is high, then remember that this is the result of a screening study, and not a diagnosis. An accurate diagnosis will require consultation with a geneticist and diagnostic methods such as chorion biopsy or amniocentesis for the purpose of prenatal karyotyping.
In 2012, another high-precision method of prenatal DNA diagnostics appeared, the uniqueness of which lies in the fact that it does not require invasive procedures (except for taking blood from a pregnant woman's vein as invasion) - Non-invasive prenatal test.

I bring to your attention a table of pregnancy outcomes with an increase in TVP:

As you can see, even with a very large TP, approximately 15% of children can be born healthy, but it is much more likely that the fetus will have CA or major developmental anomalies.

Study preparation

Biochemical screening is performed on an empty stomach (4-6 hours of fasting). More often, ultrasound and biochemistry are performed on the same day, in my opinion, this is very convenient, but if you suddenly ate recently, then you can only have an ultrasound scan, and donate blood on another day, most importantly no later than the full 13 weeks of pregnancy. Ultrasound does not require any special preparation, but a full bladder can be uncomfortable for you and the examiner.
In most cases, ultrasound is performed transabdominally (no need to undress), but sometimes you have to switch to transvaginal examination. Not infrequently, at the beginning of the study, the position of the fetus does not allow the necessary measurements to be made. In this case, you need to cough, roll over from side to side, sometimes even postpone the study for 15-30 minutes. Please be understanding.

That's it, see you in 2 weeks!

Each pregnancy is not only the joy of waiting for the baby, but also the excitement about his development and health. Even the most carefree expectant mother once thinks about it. And for some women, this anxiety even drives them into a frenzy. A hundred years ago, a pregnant woman until the very birth did not suspect what her child would be like. But today, science allows you to “peep” in advance how the baby develops. For this, a woman is sent once a trimester for routine screening. Deciphering the results of screening of the 1st trimester is an exciting process, because it is now that most developmental pathologies are being detected. But don't worry ahead of time. The screening itself is absolutely safe, and its results are likely to please and reassure you.

1st trimester screening - what is it?

Prenatal screening is a set of measures and procedures carried out to assess the course of pregnancy and the condition of the fetus.

On the one hand, if, according to the results of the examination, everything is in order with the baby, the woman has no reason to worry. On the other hand, if pathologies are identified, she gets the right to make a conscious choice that determines her future life. Therefore, there is no reason to be afraid of screening. After all, if something is wrong with the fetus, it is advisable to find out about it as early as possible in order to decide on the advisability of maintaining the pregnancy. At the same time, a woman should know that no one can force her to terminate a pregnancy, just as no one has the right to forbid her to do so.

In the first trimester, screening consists of two parts - a biochemical analysis of maternal blood and an ultrasound examination of the fetus and uterus.

Ultrasound screening of the first trimester is a procedure that should precede the rest.

It is carried out to determine the following parameters:

fetometry (sizes of individual indicative anatomical structures) of the fetus;
condition of the uterus and its appendages;
the frequency of contractions of the heart muscle;
the size of the heart, bladder, stomach;
vascular condition.

The purpose of the examination is to determine the compliance of the parameters of the fetus with accepted standards. If individual indicators differ from them, this is a reason to suspect developmental pathologies in the baby.

The second component of the first trimester screening is blood sampling from the vein of the expectant mother.

It is carried out in order to determine the level of two indicators:

the beta component of the hCG hormone;
PAPP - A or, as it is also called, protein A.

These values should also be within strict limits, and their deviation from the norm usually indicates a violation in the development of the fetus or other adverse factors that threaten pregnancy.

These include pregnant women:

over the age of 35;
who are closely related to the father of the child;
undergoing any course of treatment;
having a history of pregnancy failures;
who gave birth to children with pathologies or who have such persons in their family.

But the triggers of some pathologies are still unknown. Therefore, anomalies can also occur in a fetus whose mother does not fall into any risk group.

Of course, no one can force a woman to be screened, but refusing screening is an irresponsible decision.

Timing of the first screening

As with the next two screenings, examinations at the beginning of pregnancy should be carried out in a strictly designated period. Blood sampling and ultrasound are most informative from the tenth week to the end of the thirteenth. If you undergo procedures in the 12th week, then all organs will be visualized.

At the beginning of pregnancy, changes in the body of the embryo occur very quickly, therefore every day carries new information. In this regard, it is better to complete the first screening in one day. It is permissible to visit the ultrasound room on the previous day in order to donate blood to the laboratory in the morning of the next day.

What pathologies can be detected by first trimester screening?

Although the practice of referring every pregnant woman for screening has been around for many years, doctors rarely explain what it is for and how it “works”. Therefore, women usually go to the examination automatically, not understanding its importance. The main task of the first screening is to identify some of the most common pathologies in the fetus, if present.

Signs of Down syndrome on ultrasound

Down syndrome is a chromosomal pathology that is found in every 700th fetus. Thanks to screenings, the number of babies born with this disease has almost halved in recent years.

The disease is directly dependent on the age of the mother, therefore, all women who have reached the age of 35 automatically fall into the risk group. Pathology develops at the time of fertilization and, according to geneticists, does not depend on the lifestyle and habits of the pregnant woman. Down syndrome occurs when an extra chromosome is formed and is called trisomy 21. As a result of such a chromosomal disorder, the child develops severe heart defects, digestive organs and other systems. Children with this pathology are mentally retarded and have a characteristic appearance.

At the first screening, several facts can tell about a chromosomal disorder.

Expanded collar space. At a later date, the child develops a lymphatic system and this parameter ceases to be informative.
Nasal bone not visualized. This is true for 60-70% of children with Down syndrome. At the same time, in 2% of healthy babies, the nasal bone is also not visible at the indicated dates.
Smoothed facial features.
The blood flow is different from normal in 8 cases out of 10. But for 5% of children without any pathologies, this is the norm.
An enlarged bladder can also indicate trisomy.
Reduced, relative to the norm, the maxillary bone.
One, instead of two, umbilical artery. Such an anomaly is characteristic of many chromosomal pathologies.
Tachycardia also indicates various malformations, including Down's syndrome.

Children with this disease may well live to give birth and then exist for quite a long time. But this does not alleviate their fate as severely disabled people who constantly need help and control.

Patau Syndrome

Another chromosomal anomaly, which develops in one in 10 thousand babies. The disease is caused by an extra 13th chromosome. Genetic failure can occur at any time of gestation and affect both the entire body and only individual organs. Sometimes the pathology is mild.

On ultrasound, the doctor may suspect Patau syndrome for the following signs:

tachycardia;
asymmetric development of the cerebral hemispheres or its underdevelopment;
slow formation of the skeleton and, as a result, discrepancy between the lengths of the bones to accepted standards;
hernia caused by late formation of the abdominal muscles.

Children born with the described syndrome rarely live longer than a few months and almost never longer than a year. The most obvious signs of pathology will be distinguishable closer to the second screening.

Edwards syndrome

This is a chromosomal failure caused by the presence of a third in the 18th chromosome set. Pathology is also congenital and today there is no reliable data on what provokes it and how to prevent it. The cause of the extra chromosome is an abnormal gamete.

In a sick fetus, ultrasound fixes:

high heart rate;
the absence of the nasal bone at this time;
one umbilical artery instead of two;
umbilical hernia.

Children with Edwards syndrome are born small, although the gestation period is normal. Babies have many malformations (heart, gastrointestinal tract, lungs), which rarely allow them to live up to a year.

Smith-Opitz syndrome

This pathology is characterized by a metabolic disorder and is caused by a mutation of a certain gene. Children born with this problem may have facial anomalies, mental retardation, six-fingeredness. On the first ultrasound, the pathology has almost no characteristic signs, except for an increase in the collar space. At a later date, oligohydramnios and specific skeletal deformities may be observed. The disease is diagnosed mainly by amnio- or cordocentesis.

A gene mutation can manifest itself weakly, then it is classified as the first type and the baby has every chance of living, but lagging behind mentally and physically from peers. With the syndrome of the second type, newborns most often die.

de Lange syndrome

Another genetic failure, the causes and triggering mechanism of which have not yet been sufficiently studied. It is manifested by multiple pathologies of the skeletal structure, facial anomalies and impaired functioning of internal organs. A characteristic feature is a thin upper lip, thin, fused eyebrows and thick, long eyelashes. It is rare, only in one case out of 30 thousand.

It is almost impossible to diagnose pathology in the embryonic period. Its presence may be indicated by the absence of protein-A in the mother's blood. But it is unacceptable to make a diagnosis based only on this sign, since in 5% of cases a false positive result is also found. Closer to the second screening, the fetus may experience a discrepancy in the size of the bones to the norms.

As you can see, at the specified time, ultrasound can only reliably diagnose the presence of a pathology, but it is difficult to name its type exactly. More reliable results can be obtained by analysis of the chorionic villi or a second screening.

What do they find out at the first screening?

The data obtained in the laboratory are still intended for a doctor, and not for the inquisitive mind of a worried expectant mother. Remember that no one is specifically interested in intimidating you or hiding the real state of things. Therefore, rely on the experience of the doctor conducting the pregnancy, and give him the privilege of reading the screening protocol.

HCG norm

This hormone is called the main one during pregnancy. It grows from conception and reaches its maximum concentration by 11-12 weeks. Then it falls a little and remains at the level until childbirth.

If hCG is elevated, this may indicate:

maternal diabetes;
multiple pregnancy;
Down syndrome in the fetus;
toxicosis.

Reduced hCG is detected when:

the threat of miscarriage;
tubal pregnancy;
Edwards syndrome.

In different laboratories, the parameters may differ, therefore, one should focus not on a quantitative indicator, but on the MoM coefficient, which we will discuss below.

Norma RAPP-A

This is the name of the protein that the placenta produces. Its concentration is constantly growing. If this figure is higher than normal with other normal data, then there is no reason to worry. You should be concerned if the protein concentration is low.

This may be a sign:

chromosomal or genetic pathologies;
risk of abortion.

Heart rate (HR)

The fetal heart beats faster than that of an adult, but tachycardia may be one of the signs of developmental pathology. If the fetal heartbeat is not audible on ultrasound, then this definitely indicates a missed pregnancy.

Collar zone thickness (TVZ)

This is the most indicative parameter for the indicated period, the deviation of which from the norm almost always indicates pathologies. It is also called the thickness of the collar space. This is the distance from the skin to the soft tissues covering the neck of the embryo. Normally, this indicator, depending on the gestational age, is 0.7-2.7 mm. It is measured during the period when the length of the fetus from the head to the coccyx is in the range from 45 to 85 mm. At a later date, TVZ (TVP) becomes uninformative.

Coccyx-parietal size of the fetus (KTR)

This parameter is relevant for the 10-12th week. It is measured from the crown to the tailbone and allows you to set the gestational age as accurately as possible. Already from the end of the 12th week, the baby begins to raise his head and other parameters become indicative.

Nose bone length

The nose is a quadrangular bone, the shortening of which clearly indicates pathological processes in the development of the fetus. It happens that this bone is completely absent, which signals the most complex anomalies that are quite rare. Underdevelopment of the nasal bone (hypoplasia) may result from the described syndromes and other disorders.

Fetal head size (BDP)

In the early stages, the baby's head makes up most of his body, and the brain develops rapidly. Therefore, head size is the most important indicatorcharacterizing the condition of the fetus. Of particular importance is biparietal sizemeasured from temple to temple. If this parameter is above the norm, then the rest of the indicators are evaluated first. It happens that the fetus is just large and then all fetometry data exceed the norm. But large BDP values may also indicate cerebral hernia, tumors, or hydrocephalus.

All norms of the described data for weeks are shown in the table below.

Table 1. 1st trimester screening, norms

Please note that the deviation of some parameters by just a millimeter already speaks of pathologies, but no one excludes the banal inaccuracy of measurements. Therefore, responsibly approach the choice of the place where you will undergo the examination.

MoM coefficient

If everything is clear with the units of measurement of fetal parameters, then the results of blood biochemistry require a separate explanation. Each laboratory uses its own software and therefore results may vary. To unify the data obtained, it is customary to reduce them to a special coefficient called MoM. Indicators from 0.5 MoM to 2.5 do not cause concern. But the closer they are to one, the better. In the study protocol, the laboratory will most likely indicate the amount of hormones and then the MoM coefficient.

Getting ready for research

Due to the fact that the fetus is still very small, you will have to prepare a little for the first ultrasound. The examination can be carried out with a vaginal probe or along the anterior abdominal wall. Everything will depend on the position of the embryo.

In the first case, no preparation is required. The doctor will insert a special device, protected by a condom, into the vagina and perform gentle manipulations. The procedure does not cause any discomfort, but, within two days after it, slight bleeding may be observed.
Conducting ultrasound through the abdominal wall is absolutely safe and painless. But in order for the doctor to be able to examine the embryo, you must first fill the bladder. To do this, drink at least half a liter of liquid an hour and a half before the procedure. This is a prerequisite, without which the doctor simply will not see anything.

The light pressure of the sensor on the filled bladder is not very pleasant, but any woman can cope with these sensations. Near each ultrasound room there is a toilet where you can finally relax when the procedure is completed.

Before an ultrasound, it is also undesirable to drink carbonated drinks and eat food that provokes flatulence.

Biochemical screening of the 1st trimester is mandatory on an empty stomach.

A day before blood sampling, refrain from eating any food that can cause allergies. Even if you have never had atypical reactions to food.
Be sure to exclude nicotine and alcohol, and for the entire period of pregnancy, and not just before the tests.
Do not eat fatty and fried foods during the day before screening. It is better to exclude smoked products and products with a long shelf life.
If you take any medications on an ongoing basis, be sure to indicate this on the questionnaire. If you are undergoing any treatment, postpone the screening until it is completed if possible.

The expectant mother receives the results of the ultrasound immediately, but the response of the laboratory for biochemical analysis has to wait a week and a half.

Deciphering the results

Having received the ultrasound and biochemistry data, the woman goes to her gynecologist, who analyzes the information received. If the results are satisfactory and the woman is not at risk, no additional tests are required. There is no point in further examinations in the case of a frozen or regressing pregnancy. When the screening data is unsatisfactory, a woman is recommended to consult a geneticist.

Deciphering research data on your own is risky. But if you are itching to understand the numbers that are on hand, note that the laboratory usually gives results in the form of a fraction. The closer its value is to 1, the more serious the situation. That is, an indicator of 1:10 is much worse than 1:100, and 1:100 is worse than 1:300. This ratio shows how many healthy children in your conditions account for one with the indicated pathology. For example, if you found the entry "trisomy 21 - 1:1500" in the lab's response, this means that the risk of having a baby with Down's disease is 1 in 1500. This is a very small probability and you can relax. The boundary ratio is considered to be 1:380.

Remember that even a high risk is not yet a reason for panic, and even more so for an urgent termination of pregnancy. You still have invasive diagnostic methods.

And only they can give a clear answer whether your baby has a pathology, and not in theory in a group of people with similar parameters.

Safety for mother and fetus

By itself, prenatal screening of the 1st trimester does not pose any danger to either the mother or the fetus. Ultrasound does not affect the fetus, although it is not known for certain whether the examination causes discomfort to the baby. Some experts are of the opinion that the child hears a strong noise during the procedure, which may be unpleasant for him, but definitely not dangerous.

Blood for biochemistry is taken from a future mother from a vein, which is also completely harmless, although not very pleasant. Some women are very afraid of this procedure and even lose consciousness in the process. If you are in this category, tell the nurse to have ammonia ready.

If the results obtained are satisfactory, then this is usually stopped until the next screening. When the data raises concerns, you will need to resort to additional diagnostic methods. At the beginning of pregnancy, this is a chorionic villus biopsy or amniocentesis. The first method allows you to determine with 100% accuracy whether there are congenital pathologies in the fetus, but too often it leads to a miscarriage. Amniocentesis is less dangerous, but even this procedure results in a spontaneous abortion in one in 200 cases.

What to do with adverse results?

Absolutely unequivocally, the doctor should interpret the results of screening. Not having sufficient knowledge, the expectant mother will only bring fear upon herself, not understanding the numbers received. For example, the borderline data for Down's disease is very likely to be in a 40-year-old woman who becomes pregnant through IVF. This does not mean at all that something is wrong with her pregnancy specifically. The risks of pathology in the group of women of this age are simply high.

Therefore, having received results that inspire concern, discuss with your doctor. And maybe not just one. If finances allow, take the tests in another laboratory. Often, doctors recommend not to panic ahead of time and wait for the results of the second screening, which can be done starting from the 15th week.

On which ultrasound can a doctor determine the sex of a child?

Ultrasound is not only a diagnostic method, but also an opportunity to know in advance the gender of your baby. Theoretically, this becomes possible already from the 12th week, when the labia in girls and the penis in boys are visualized. A more realistic period when gender can already be determined unmistakably is fifteen weeks. The only problem is that the fetus turns in the right place to the sensor. Alas, this does not happen at the request of the mother and does not depend on the manipulations of the doctor. Sometimes, despite all the tricks, the baby does not reveal his main secret until the very birth.

Screening is not a cause for concern, but simply a diagnostic tool. Today, thanks to the Internet, expectant mothers have access to all the knowledge of the world. Unfortunately, the information available is often misleading and scary. But now, when you are already responsible for two lives, the main thing is not to worry. Therefore, do not expect unpleasant surprises from pregnancy and follow the doctor's instructions.

Goals

Those who have already passed the first comprehensive examination, know and understand very well why they do the second screening during pregnancy. The goals of this procedure are:

identify those defects that could not be determined after the first screening;
confirm or refute the diagnoses previously made in the first trimester;
establish the level of risk of pathologies;
to detect physiological deviations in the formation of the child's body systems.

high hCG;
low EZ and AFP.

all blood counts are low.

Neural tube defect:

normal hcg.
high E3 and AFP.

Not always a bad second screening guarantees a 100% accurate diagnosis. There were cases when quite healthy children were born after it. Even medicine fails. But you should not count on the fact that this is exactly your case. In this matter, it is better to focus on the opinion and recommendations of the gynecologist observing the pregnancy. It is he, as a professional, who can take into account the possibility of a false result, which is determined by many different factors.

False results

Although rare, this happens: second trimester screening gives false results. This is possible if the course of pregnancy is characterized by the following features:

multiple pregnancy;
incorrectly set deadline;
excess weight overestimates the indicators, insufficient - underestimates them;

Before the second screening, the gynecologist must identify these factors with the help of a questionnaire and a preliminary examination and take them into account when deriving the results. It is on this that further actions to preserve or terminate the pregnancy will depend.

Next steps

Since the second screening during pregnancy is carried out already in its middle, abortion in case of detection of severe genetic abnormalities is impossible. What actions can the doctor advise in this case?

Consultation with a gynecologist about the data obtained if the risk of developing abnormalities is 1:250 or 1:360.
Carrying out invasive diagnostic methods at the risk of pathologies 1:100.
When confirming the diagnosis, which is not amenable to therapeutic adjustment, it is recommended that the fetus be removed.
If the pathology is reversible, treatment is prescribed.

The second screening quite often ends in forced labor, and the couple must be mentally prepared for this. Since a lot depends on these procedures, young parents need to know as much information about them as possible, which will help to understand incomprehensible issues and dispel doubts.

And other features

Before the second screening procedures, a couple always has a lot of questions about how to properly prepare for them and how exactly they go. The doctor does not always have time to conduct detailed educational work on this matter, so you often have to look for answers yourself. A special block will help to facilitate this task.

When is the second screening done?

From the 16th to the 20th week.

Do I need to donate blood at the second screening?

If the ultrasound showed deviations, then it is necessary. If there are no suspicions of genetic disorders, the doctor may not prescribe a blood biochemistry test.

What is included in the second screening during pregnancy?

Ultrasound and biochemical analysis of blood taken from a vein.

What is revealed at the second screening?

Genetic disorders in the development of the fetus and placenta.

Is it necessary to do a second screening?

At the first bad screening - definitely.

How should hCG change at the second screening?

Compared to the results of the first screening, its indicators are temporarily reduced.

Can I eat before the second screening?

You can not eat 4 hours before the second screening, as this may distort the results of the studies.

In some cases, doubts about whether the fetus has developmental abnormalities can only be dispelled or confirmed by a second screening. If the results of the first showed too high a risk of gene mutations, but the pregnancy was not terminated, a comprehensive study must be completed. This allows not only to soberly assess the situation, but also to make an informed decision about whether to give birth to a sick baby or not. The question is difficult, but it is impossible not to pay attention to it: not only the life of the child, but also the fate of the parents themselves depends on it.

This type of examination is prescribed for women who are diagnosed with 11-13 weeks of pregnancy. The initial stage of the first screening during pregnancy is an ultrasound examination. After that, the pregnant woman is sent for a biochemical blood test.

Such events make it possible to identify genetic defects, pathologies in the structure of the embryo and respond to them in a timely manner.

How to prepare for the first screening?

The procedure under consideration includes two types of examination, each of which needs a certain preparation.

ultrasound

Can be done in two ways:

External (abdominal). It is given with a full bladder, therefore, 30-60 minutes before the start of the procedure, the pregnant woman must drink at least half a liter of purified water without gas, or not urinate 3-4 hours before the start of the ultrasound.
Vaginal. This type of examination does not require special preparation. Some clinics require patients to come to the appointment with their own diaper, sterile gloves and a condom for the ultrasound transducer. All this can be purchased at almost any pharmacy.

(double test)

It provides for the following preparatory measures, ignoring which can significantly affect the test results:

2-3 days before the analysis, a pregnant woman should refrain from fatty, salty foods (meat, seafood), citrus fruits and chocolate. The same goes for multivitamins.
Blood must be donated on an empty stomach. The last meal should be at least 4 hours before the test.
Doctors also advise to exclude sexual intercourse a couple of days before the screening.

How does the first screening in pregnant women go and what does it show?

The indicated type of examination should be started with. After all, it is ultrasound diagnostics that makes it possible to determine the exact gestational age - and this very important for the second stage of screening: the double test. After all, the indicators of the blood norm, for example, for 11 and 13 weeks will be different.

In addition, if an ultrasound scan detects the fetal fading or the presence of serious anomalies in it, there will be no need for a biochemical blood test.

Thus, at the time of passing the second stage of the first screening, the pregnant woman should have the conclusion of an ultrasound doctor in her hands.

Ultrasonography

The type of examination under consideration favors the identification of such physical defects of the fetus:

developmental delay.
The presence of serious pathologies.

Also thanks to ultrasound the gestational age is determined, the number of fetuses in the uterus, the approximate date of birth is set.

In the first third of pregnancy, the following indicators are checked on an ultrasound machine:

The distance from the coccyx to the parietal part of the head. This parameter is also called the coccygeal-parietal size (KTP). At the 11th week of pregnancy, the CTE varies within 42-50 mm, at the 12th week - 51-59 mm, at the 13th - 62-73 mm.
The size of the nasal bone. At the 11th week, it is not visualized. At 12-13 weeks, its parameters are more than 3 mm.
The distance between the tubercles of the parietal region, or biparietal size (BDP). Normally, this indicator should be 17 mm at the 11th week; 20 mm at 12 weeks; 26 mm at the 13th week of pregnancy.
Embryo head circumference.
The distance from the forehead to the back of the head.
The structure of the brain, symmetry and size of its hemispheres, the quality of the closed skull.
Heart rate (HR). By means of this parameter, cardiac arrhythmia can be detected. When measuring the heart rate, the sonographer must be very careful: due to the short duration of pregnancy, it is possible to confuse the pulsation of the patient's vessels with the heartbeat of the embryo. Normally, the indicator in question varies between: 153-177 at the 11th week of pregnancy; 150-174 - at the 12th week; 147-171 - on the 13th.
Parameters of the heart and its arteries.
The structure of the femur, shoulder, tibia.
The distance between the inner and outer surface of the skin of the neck, or the thickness of the collar space (TVP). Normally, this indicator will be: at the 11th week of pregnancy 1.6-2.4 mm; at the 12th week - 1.6-2.5 mm; at the 13th week - 1.7-2.7 mm.
The structure of the chorion (placenta), its location. Upon detection of exfoliation of the chorion, its volumes are established and whether there is a tendency to progress. A similar phenomenon can provoke spotting and complaints of a pregnant woman about pain.
Shape and size of the yolk sac, the quality of supply of the umbilical cord with vessels. The yolk sac normally decreases in size by the 12th week of pregnancy, and at the time of the procedure it should be a tiny (4-6 mm) cystic neoplasm of a rounded shape.
The structure of the uterus, its appendages. Particular attention is paid to the ovaries: in the later stages of pregnancy, it is problematic to examine them.

At the time of the first screening ultrasound the fetus must be positioned correctly so that the specialist can carry out a qualitative inspection and make the necessary measurements.

If the child is not positioned correctly, the patient is asked to roll over from her back to her side, cough, or squat.

Double test (norms and interpretation)

For this type of examination, blood is used from a vein, which is taken on an empty stomach.

Biochemical screening is needed to determine the following parameters:

1.Protein Pregnancy (PAAP) -A )

This protein is produced by the placenta and increases with the course of pregnancy.

Normally, the indicators of this protein will be as follows:

11-12 weeks: 0.77-4.76 honey / ml.
12-13 weeks: 1.04-6.01 mU / ml.
13-14 weeks: 1.48-8.54 mU / ml.

A reduced amount of PAAP-A may be due to the following deviations:

There is a threat of miscarriage.
The developing embryo has Down syndrome, Edwards syndrome, or another genetic disease.

An increase in the level of PAAP-P in the blood of a future mother often does not have an important diagnostic value.

2. Amounts of human chorionic gonadotropin (hCG)

This hormone is produced in the first weeks of pregnancy, reaching a maximum level at the 12th week of pregnancy, after which the amount of the hormone in question decreases.

By studying the indicators of the amount of hCG in the blood of a pregnant woman, it is possible to determine the presence / absence of chromosomal abnormalities.

In the conclusion sheet, this parameter is written in the column “free β-hCG”.

In the first trimester of pregnancy, the norm of this hormone is as follows:

11th week: 17.3-130.2 ng / ml.
12th week: 13.3-128.4 ng / ml.
13th week: 14.3-114.7 ng / ml.

Elevated levels of hCG may indicate several phenomena:

A developing fetus has Down syndrome.
The mother-to-be has diabetes.
The pregnant woman suffers from severe toxicosis.

A decrease in the level of the hormone in question may occur against the background of the following factors:

There is a risk of miscarriage.
Pregnancy formed outside the uterine cavity
Failure of the placenta to perform its basic functions.
The fetus has Edwards syndrome.

What pathologies can be detected on the screening of the first trimester?

In the first three months of pregnancy, through examinations, it is possible to identify or suspect the presence of the following ailments:

Errors in the structure of the neural tube (meningocele).
Down Syndrome. The prevalence of this disease: 1:700. Timely detection of this pathology made it possible to reduce the birth rate of sick babies (1 per 1100 cases).
Umbilical hernia (omphalocele). Ultrasound examination shows that the internal organs are in the hernial sac, and not in the abdominal cavity.
Edwards syndrome (1:7000). It is characterized by a reduced heart rate, omphalocele, insufficient number of blood vessels on the umbilical cord, absence (inability to visualize) the nasal bone. Pregnant women over 35 years of age are at risk.
triploidy. With this pathology, instead of 46, there are 69 chromosomes in a fertilized egg. Such a phenomenon may occur due to an incorrect structure of the egg, or when two spermatozoa penetrate one egg. Often, with such anomalies, women do not bear a fetus, or give birth to dead children. In those rare cases when it was possible to give birth to a live baby, the period of his life is limited to a few days / weeks.
Patau disease (1:10000). Ultrasound ascertains retardation in the structure of the brain, tubular bones, increased heart rate, omphalocele. Often, babies that are born with a similar diagnosis live a maximum of a couple of months.
Smith-Lemli-Opitz syndrome (1:30000). It is the result of genetic disorders, due to which the qualitative assimilation of cholesterol is impossible. The pathology under consideration is capable of provoking many malformations in development, the most serious of which are errors in the functioning of the brain and internal organs.

To confirm some of the above pathologies, it is required additional diagnostic measures, and in most cases they are invasive.

What can affect the results, and can the doctor make a mistake at the first screening?

Screening for the first trimester of pregnancy has certain disadvantages.

On the other hand, it is still necessary to conduct an examination: the timely detection of a particular pathology will make it possible to terminate the pregnancy (if the fetus is with severe deviations), or take measures to maintain the pregnancy (if there is a threat).

In any case, it will be useful for any expectant mother to know that false positive screening results can occur in the following situations:

ECO. With artificial insemination, the parameters of the occipital part of the embryo will be 10-15% higher than normal. A double test will show an increased amount of hCG, and a low level (up to 20%) of PAAP-A.
Weight of the expectant mother: severe thinness is a consequence of a decrease in the amount of hormones, and with obesity, the opposite phenomenon is observed.
Diabetes, other diseases associated with the functioning of the thyroid system. With such ailments, it is problematic to calculate the risks of diseases in the fetus. Often, doctors cancel screening for this reason.
Multiple pregnancy. Due to the impossibility to this day to accurately determine the hormonal background of a pregnant woman who is carrying more than 1 child, her screening is limited to ultrasound and does not provide for biochemical analysis.

Most expectant mothers feel in one way or another fears about the baby in the womb. As a rule, they do not have soil under them. But in some cases, these fears are so strong that it is better for the expectant mother to undergo a first trimester screening and continue to wait for the baby calmly. Sometimes this study is recommended by doctors to allow the pregnant woman to decide whether to prolong the pregnancy or the risks are too high.

All pregnant women can undergo screening in the first trimester with the consent of both future parents of the baby. In cases where these are the doctor's recommendations, and the risk of having a sick baby is increased, this examination should be done without fail.

Among the reasons that should encourage a pregnant woman to undergo the first screening during pregnancy will be:

Close family relationship of the pregnant woman with the father of the baby;
The presence of close relatives of both parents with congenital pathologies;
The presence of a pregnant baby with congenital pathologies;
Age of the future mother (over 35 years old).

Among the reasons for screening in the first trimester will also be those related to the woman's previous pregnancies:

Presence of fetal fading;
stillbirth;
Having 2 or more miscarriages;

Risk factors will also include those cases that are associated with:

With the use of drugs prohibited during pregnancy (even when it was vital);
With the mother, during pregnancy, viral or bacterial diseases.

The referral for the first screening will be written by the gynecologist who observes the pregnant woman. But the place of examination must be chosen by the pregnant woman herself.

It should be noted here that this survey is carried out in 2 stages. The first is an ultrasound, and the second is a biochemical blood test, where the amount of hCG and PAPP-A hormones is determined. It would be better if both examinations are carried out by a woman on the same day, and for this it is good to choose a perinatal center where they are both done.

How is the research done?

An ultrasound should be done first, and then blood sampling from a vein for hCG and PAPP-A.

Ultrasound screening of the 1st trimester is carried out in two ways:

transvaginally
Abdominally

The doctor will choose only one of the ways. In a transvaginal exam, a very thin probe is inserted into the vagina. To do this, the woman lies on the couch without clothes below the waist, bends her knees and slightly spreads. A transducer placed in a condom is inserted into the vagina. No discomfort is observed. But sometimes on the second day there may be slight spotting.

In abdominal screening, the examination is done through the abdomen and requires a full bladder. And you should be prepared for this. In this case, the sensor is located on the skin of the abdomen. Here you just need to lie down on the couch and free your stomach from clothes. During the second screening (in the second trimester), abdominal filling of the bladder is not required.

The results of the ultrasound will be handed out and they need to undergo biochemical screening.

Biochemical screening, what is it?

The second screening is blood sampling from a vein. During its conduct, in addition to the results of ultrasound, the pregnant woman will be asked a number of questions that are essential for screening.

Then 10 ml of blood will be taken from a vein. The results of this examination are usually ready no earlier than in a few weeks (hCG and PAPP-A). Then they will issue a conclusion.

Dates

First trimester screening is very time-limited. The accuracy of the result will depend on the correctness of their determination. Therefore, it is important to conduct an examination no earlier than the 1st day of the 11th week and no later than the 6th day of the 13th week of pregnancy. If necessary, this examination, the calculation of the period is made taking into account the anamnesis, as well as the last menstruation. Usually, when referring to a screening by a gynecologist, pregnancy calculations are performed again and the day of the examination is determined.

Training

Such a complex and responsible procedure requires some preparation. In order to prepare well for screening, a number of features of the procedure should be taken into account. Since two examinations are performed at once: an ultrasound examination and blood sampling from a vein, they differ somewhat in preparation. The general will be the preparation on the day before the examination (it is also possible two or three days before). This screening preparation is needed

for more accurate results of a biochemical blood test (hCG and PAPP-A). Here is the diet to follow:

Eliminate allergenic foods from the diet;
Do not eat fatty and fried foods;
Do not eat seafood and smoked meats;
Don't eat chocolate.

Non-compliance with the diet will lead to an increased risk of not. Directly on the day of the procedure, you should fast 4 hours before donating blood for a biochemical analysis, if the ultrasound is performed abdominally, 30 minutes - 1 hour you should start drinking water without gas or you can, if possible, not urinate 2-3 hours before the examination . When examining transvaginally, no preparations are needed. As noted earlier, you first need to undergo (usually before 11 o'clock in the afternoon) an ultrasound examination, and then donate blood.

Deciphering the results

Deciphering the results, most often, takes a long time (up to 2-3 weeks). It is carried out using a special program prisca. The decoding includes not only ultrasound and biochemical screening, but also monitoring the condition of the pregnant woman, as well as family history. One of the points will be the question: is it necessary to undergo a re-examination at a later date?

More screening results will answer a large number of questions. Among which will be:

How high is the risk of congenital pathologies in the fetus?
Which of the possible genetic diseases are possible and what is their probability?
Should pregnancy be prolonged?

In ultrasound, five main criteria are determined, they can say a lot about possible pathologies and the likelihood of their occurrence.

So, the first screening will show the parameters of the coccyx-parietal size (KTR) of the fetus, which are an indicator of the overall development of the fetus and are characterized very individually for each week.

For the possible development of some chromosomal diseases, it is important to study the thickness of the collar zone (TVZ) in case of deviation from the norm, there is a suspicion of Down syndrome and some other complex chromosomal pathologies.

In this regard, the nasal bone is also very important. Which, in a fetus with this disease (60–70%), is formed much later or is absent. It is not determined by ultrasound in about 2% of healthy children. Much later, it is also determined in pathologies such as Pattau's syndrome. The norm, when it is visible already at 11 weeks.

One of the important conditions for the absence of pathologies will be heart rate. Its violation may indicate several pathologies: Down syndrome, Edwards syndrome, Pattau syndrome.

During this period, the presence of an umbilical hernia (omphalocele) is already determined, when the internal organs of the peritoneum are in a thin bag of skin outside the abdominal cavity.

They also look for the presence of reverse venous blood flow, which indicates trisomy (the presence of a triple of chromosomes instead of two, which usually indicates the occurrence of severe genetic diseases).

And the presence of one umbilical artery instead of two, which is often a sign of Edwards Syndrome or indicates an omphalocele.

The table below shows the data that represent the norm for the fetus at this stage of development. Comparing with them the data of ultrasound screening of the first trimester of a pregnant woman, one can judge the development of the fetus.

Indicators of screening studies in the first trimester of pregnancy (normal)

What hormone norms are determined by the first screening

When conducting biochemical screening (blood test), the level of two types of hCG and PAPP-A hormones is determined:
HCG (chorionic gonadotropin) is a hormone that is called the hormone of pregnancy, its amount in the body of a woman increases when pregnancy occurs (a pregnancy test is based on this factor). It is bad if its level is increased or decreased. With elevated rates, the risk of developing Down syndrome increases, with lower rates, the risk of Edwards syndrome or placental pathology. The table below shows the normal values.

The second hormone that is being studied is called PAPP-A (plasma protein-A). This is the protein that the placenta produces, and, therefore, with an increase in the duration of pregnancy, its concentration in the blood increases. By the amount of PAPP-A produced, it is possible to judge some chromosomal pathologies of the fetus. Among them will be:

Edwards syndrome;
Down syndrome;
Cornelli de Lange syndrome
Rubinstein-Taybi Syndrome
Mental underdevelopment with hypertrichosis.

The fact is that at these times the screening ultrasound examination is not always accurate enough, so the results of biochemical screening are very important. If the result is increased or decreased in comparison with the norm, then this is already an alarming bell.

The table below shows the results of screening, in which the norm for this hormone is observed.

MoM coefficient

When handing over the results, there will be such an indicator as the MOM coefficient.

The fact is that there is a norm for a given area and the age of a pregnant woman, which, using a special prisca program, is converted into a median. The ratio of the indicators of a pregnant woman to this norm will be an indicator of MoM. Normally, when the indicator ranges from 0.5 to 2.5, and ideally when it is close to 1. The entry in the result form should look something like this “hCG 1.2 MoM” or “PAPP-A 2.0 MoM”, if this indicator is increased - it is always bad.

Research Risks

In addition to the MoM indicators in the results form, there will also be a risk assessment: which can be “High” or “Low”, normally when it is “Low”. Usually this is a number with a fraction, for example, 1:370, the larger the fraction, the better. It is desirable that the figure be greater than 380. This means that at the birth of 380 babies, one child may have Down's disease. Here, the higher the number (more than 380) the better. Such risks are defined as "Low".

Important. At the conclusion with the record "high risk", the ratio is in the range from 1:250 to 1:380, as well as MoM indicators for one of the hormones in the range below or above the corridor of 0.5-2.5 units. Screening is considered poor.

The picture shows an example of filling out the form, the screening of the 1st trimester is given, this result is deciphered and is characterized as “Low result”, i.e., good. So we see the record “Expected risks of trisomy” with the numbers: 21, 18, 13 - these are severe genetic diseases: Down's disease, Edward's Syndrome, mental underdevelopment with hypertrichosis, but the individual numbers are very large. Which makes the risks of having a sick baby very low.

What can affect the results?

First of all, it should be noted that with twin screening results are not reliable, here the indicators can be very different, they are usually not interpreted by geneticists. This is especially true for biochemical screening for hormones (hCG and PAPP-A), the result of which is usually significantly increased.

There are a number of other factors that affect the results:

First of all, it is ECO. Here, the PAPP-A indicators will be changed (lower by 10-15%);
In addition, a condition such as pregnancy obesity will also give an increase in the level of all hormones (hCG and PAPP-A too);
If the weight of the pregnant woman is very low, then the level of hormones will be below normal;
Reduces hormonal levels and diabetes;
It is not recommended to screen for the first trimester after an amniocentesis (this is a sampling for amniotic fluid analysis). Donating blood is not recommended here.
And also the usual fear of a pregnant woman before the procedure can affect the results. So far, fear cannot be diagnosed, and its effect on the body of a pregnant woman has not been studied. There is no way to predict the results.

What to do in case of bad tests

If the results sheet contains the phrase "High risk", then this means that the results are poor.

In this case, most likely, the pregnant woman will be asked to visit a genetics doctor. At a consultation, which will consider several options (depending on the results of screening) for the further development of pregnancy:

The first thing a doctor might recommend is to get screened in the second trimester, and then, possibly, in the third trimester.
In more complex cases, it will be recommended (sometimes the recommendations are very urgent) to conduct an invasive diagnosis. Chorionic villus biopsy, amniocentesis, or cordocentesis may be among the suggested options.
And based on the results of these invasive diagnostics (or one of them), the issue of prolonging the pregnancy will be considered.

Instead of conclusions

The screening procedure for the first trimester is a complex and troublesome business. But in many cases, it is necessary in order to determine possible deviations in the development of the fetus in the early stages. Sometimes this will be a signal for closer monitoring of the course of pregnancy, and in some cases a signal for action, which will help a healthy baby be born.

Unfortunately, medicine is not omnipotent and in some cases it is possible to predict the birth of a baby with chromosome disorders, but it cannot be cured, then only the pregnant woman and the father of the child will decide the fate of this pregnancy.

Sometimes screening of the first trimester is important for purely psychological reasons - it will allow the pregnant woman to overcome the fears that overcome her. And this will be the key to the health of the baby and mother, will help to get the desired peace of mind and self-confidence.

What does 1st trimester screening show? This is an ultrasound examination that helps to determine the possible presence of chromosomal disorders at an early stage of pregnancy. During this period, women should also undergo a blood test for and PAPP-A. If it turned out that the screening results of the 1st trimester are poor (ultrasound and blood counts), then this indicates a high risk of having Down syndrome in the fetus.

Screening norms of the 1st trimester and their interpretation

During ultrasound, the thickness of the cervical fold in the fetus is examined, which should increase proportionally as it grows. An examination is carried out at the 11-12th week of pregnancy, and the neck fold should be from 1 to 2 mm at this time. By week 13, it should reach a size of 2-2.8 mm.

The second of the indicators of the 1st trimester screening norm is the visualization of the nasal bone. If it is not visible during the examination, then this indicates the possibility of a risk of Down syndrome in 60-80%, but it is believed that in 2% of healthy fetuses, it may also not be visualized at this time. By 12-13 weeks, the normal size of the nasal bone is about 3 mm.

In the process of conducting an ultrasound scan at week 12, the age and approximate date of birth of the child are determined.

1st trimester screening - interpretation of blood test results

A biochemical blood test for beta-hCG and PAPP-A is deciphered by translating the indicators into a special MoM value. The data obtained indicate the presence of deviations or their absence for a given gestational age. But these indicators can be influenced by different factors: the age and weight of the mother, lifestyle and bad habits. Therefore, for a more accurate result, all data is entered into a special computer program, taking into account the personal characteristics of the expectant mother. This program shows the results of the degree of risk in the ratio of 1:25, 1:100, 1:2000, etc. If we take, for example, the 1:25 option, this result suggests that for 25 pregnancies with indicators like yours, 24 children are born healthy, and only one has Down syndrome.

After the 1st trimester blood test is screened and based on all the final data received, the laboratory can issue two conclusions:

Positive test.
Negative test.

In the first case, you will have to undergo a deeper examination and. In the second option, additional studies are not needed, and you can safely wait for the next scheduled screening, which pregnant women undergo during the 2nd trimester.

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Bibliographic link

Screening of the 1st (first) trimester. Screening times. Screening results. ultrasound screening.

1st trimester screening - what is it?

It is carried out to determine the following parameters:

It is carried out in order to determine the level of two indicators:

These include pregnant women:

Timing of the first screening

What pathologies can be detected by first trimester screening?

Signs of Down syndrome on ultrasound

At the first screening, several facts can tell about a chromosomal disorder.

Patau Syndrome

On ultrasound, the doctor may suspect Patau syndrome for the following signs:

Edwards syndrome

In a sick fetus, ultrasound fixes:

Smith-Opitz syndrome

de Lange syndrome

What do they find out at the first screening?

HCG norm

If hCG is elevated, this may indicate:

Reduced hCG is detected when:

Norma RAPP-A

This may be a sign:

Heart rate (HR)

Collar zone thickness (TVZ)

Coccyx-parietal size of the fetus (KTR)

Nose bone length

Fetal head size (BDP)

MoM coefficient

Getting ready for research

Deciphering the results

Safety for mother and fetus

What to do with adverse results?

On which ultrasound can a doctor determine the sex of a child?

Related videos

Goals

False results

Next steps

And other features

How to prepare for the first screening?

ultrasound

(double test)

How does the first screening in pregnant women go and what does it show?

Ultrasonography

In the first third of pregnancy, the following indicators are checked on an ultrasound machine:

Double test (norms and interpretation)

What pathologies can be detected on the screening of the first trimester?

What can affect the results, and can the doctor make a mistake at the first screening?

How is the research done?

Biochemical screening, what is it?

Dates

Training

Deciphering the results

Indicators of screening studies in the first trimester of pregnancy (normal)

What hormone norms are determined by the first screening

MoM coefficient

What can affect the results?

Instead of conclusions

Screening norms of the 1st trimester and their interpretation

1st trimester screening - interpretation of blood test results