Doppler ultrasound during pregnancy: how and when doppler is done, its interpretation and norms. Screening for the first trimester of pregnancy - what you need to know about rates and results Ductus venosus pi rate 13 weeks
Screening of the 1st (first) trimester. Screening timeline. Screening results. Ultrasound screening.
Your baby has overcome all the difficulties and dangers associated with the embryonic period. I safely reached the uterine cavity through the fallopian tubes, there was an invasion of the trophoblast into the endometrium, the formation of a chorion. The embryo grew and changed incredibly every week, the rudiments of all the most important organs and systems were formed, the body, head, limbs were formed.
Finally he grew up to 10 weeks, having acquired all those necessary features, a baby-like configuration, which made it possible to call him a fetus from that moment.
The time has come for the screening of the 1st (first) trimester.
Today we will talk about the timing of the first trimester screening, the results of the ultrasound screening.
This topic is extensive and of course you can't get off with one article here. We have to disassemble many anomalies and malformations that may already be suspected or even diagnosed at this time. But let's start over.
What is screening?
Screening is a set of necessary measures and medical research, tests and other procedures aimed at preliminary identification of persons, among whom the probability of having a certain disease is higher than that of the rest of the surveyed population. Screening is only the initial, preliminary stage of the population survey, and persons with positive screening results need a subsequent diagnostic examination to establish or exclude the presence of a pathological process. The impossibility of carrying out diagnostic tests that allow to establish or exclude the presence of a pathological process with a positive screening result makes the screening itself meaningless. For example, biochemical screening of fetal chromosomal diseases is not justified if subsequent prenatal karyotyping is not possible in the region.
Conducting any screening program should be accompanied by a clear planning and assessment of the quality of the screening, since any screening test performed in the general population may do more harm than good for the people being examined. The concept of "screening" has fundamental ethical differences from the concept of "diagnostics", since screening tests are carried out among potentially healthy people, therefore it is very important that they have a realistic idea of the information that this screening program provides. For example, when conducting ultrasound screening of fetal chromosomal pathology in the first trimester of pregnancy, women should not have the impression that detecting an increase in the thickness of the collar space (TVP) in a 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 disease, just as a positive test result does not indicate its presence.
When and why was the first trimester screening invented?
Every woman has a certain risk that her child may have a chromosomal abnormality. It is for everyone, and no matter what way of life she leads and social status.
In a 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, at a period of 11-13 (+6) weeks.
So, first trimester screening is a set of medical studies conducted for a period of 11-13 (+6) weeks, and aimed at preliminary identification of pregnant women, among whom the likelihood of having a child with chromosomal abnormalities (CA) is higher than in other pregnant women.
The main place among the identified CA is occupied by Down's Syndrome (trisomy on 21 pairs of chromosomes).
The English physician John Langdon Down was the first in 1862 to describe and characterize the syndrome, later named after him, as a form of mental disorder.
Down's syndrome is not a rare condition - 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 susceptible to the syndrome. In 1959, Jerome Lejeune discovered that Down syndrome occurs due to trisomy of the 21st pair of chromosomes, i.e. the karyotype is represented by 47 chromosomes instead of the normal 46, since chromosomes of the 21st pair, instead of the normal two, are represented by three copies.
In 1970, the first method of screening for trisomy 21 in the fetus was proposed, based on an increase in the likelihood of this pathology with increasing age of a pregnant woman.
At screening based on the age of the mother, only 5% of women will fall into the “high risk” group, and this group will include only 30% of the fetuses with trisomy 21 of the entire population.
In the late 1980s, screening methods appeared that took into account not only age, but also the results of studying the concentration of biochemical products of fetal and placental origin in the blood of a pregnant woman, such as alpha-fetoprotein (AFP), unconjugated estriol (uE3), chorionic gonadotropin (hCG ) and inhibin A. This screening method is more effective than screening only by the age of a 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 size of the TVP (thickness of the collar space) of the fetus at 11–13 (+6) weeks of gestation. This screening method can detect up to 75% of fetuses with chromosomal abnormalities with a false-positive rate of 5%. Subsequently, the screening method based on the age of the mother and the size of the fetal TBP at 11-13 (+6) weeks of pregnancy was supplemented by the determination of 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 with ultrasound examination at 11-13 weeks in 60-70% of fetuses with trisomy 21 and in 2% of fetuses with normal karyotype, the nasal bones are not visualized. The inclusion of this marker in a screening method based on ultrasound examination and determination of biochemical markers in the first trimester of pregnancy allows an increase in the frequency of detection of trisomy 21 up to 95%.
What US - markers that increase the risk of CA, are we assessing?
First of all, this is the expansion of the thickness of the collar space (TVP), lack of visualization of the nasal bones, reverse blood flow 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 fetus's neck in the first trimester of pregnancy.
- The term "space" is used regardless of whether this space has a septum or not, whether it is localized in the neck or extends to the entire fetal body.
- The incidence of chromosomal diseases and malformations in the fetus depends on the magnitude of the TVP, and not on its ultrasound characteristics.
- In the second trimester of pregnancy, the collar space usually disappears or, in rare cases, transforms into either neck edema or cystic hygroma in combination with or without generalized fetal edema.
1 Measurements are made at 11–13 (+6) weeks of pregnancy with the size of the parietal-coccygeal 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 turns out to be 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 Measurement should be carried out strictly in the sagittal section of the fetus, and the fetal head should be in a neutral position.
3 The image should be enlarged so that only the head and upper chest of the fetus are visible on the screen.
4 The size of the image should be enlarged so that the minimum cursor movement gives a change in size of 0.1 mm.
5 Collar thickness should be measured at its widest point. It is necessary to differentiate the echo structures of the fetal skin and the amniotic membrane.
6 Cursors should be placed on the inner boundaries of the echo-positive lines delimiting the collar space, without going over it.
7 During the study, it is necessary to measure the TVP several times and select the maximum of the obtained measurements.
In 5-10% of cases, the umbilical cord is entwined around the neck, this can lead to a false increase in TVP. In such cases, the measurement of TVP should be taken on either side of the umbilical cord, and the average of the two measurements is used to assess the risk of fetal chromosomal abnormalities.
Imaging of the nasal bones of the fetus
- Should be carried out at 11–13 (+6) weeks of gestation and at a 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 displayed 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 imaging the nasal bone, three separate lines should be present. The upper line represents the skin of the fetal nose, the lower line, which is more echogenic and thicker, represents the nasal bone. The third line is a continuation of the first, but is located slightly higher than it and represents the tip of the fetus's nose.
- At 11-13 (+6) weeks, a fetal profile can be obtained and assessed in more than 95% of fetuses.
- With a normal karyotype, the absence of visualization of the nasal bones is characteristic of 1% of fetuses in women of the European population and for 10% of fetuses in women of the Afro-Caribbean population.
- The bones of the nose are not visualized in 60–70% of fetuses with trisomy 21, in 50% of fetuses with trisomy 18 and in 30% of fetuses with trisomy 13.
- With a false-positive rate of 5%, a combination screening that includes measurement of TBP, imaging of the fetal nasal bones, and measurement of maternal serum PAPP-A and β-hCG concentrations has the potential to detect more than 95% of fetuses in trisomy 21.
This fruit is one of the dichorionic twins. TVP and blood flow in the ductus venosus are normal, but there is no visualization of the nasal bones. The result of karyotyping is Down's Syndrome, the karyotype of the 2nd twin fetus is normal.
Venous duct doppler and tricuspid regurgitation
With chromosomal abnormalities, malformations of various organs and systems are often formed, including congenital malformations of the cardiovascular system.
The ductus venosus is a unique shunt that delivers oxygenated blood from the umbilical vein, which is directed primarily through the foramen ovale into the left atrium, to the coronary and cerebral arteries. The blood flow in the venous duct 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 ductus venosus is combined with the presence of chromosomal abnormalities or heart defects in the fetus and is a sign of a possible unfavorable pregnancy outcome. At this stage of pregnancy, 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 regugitation is a wave of reverse blood flow 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 ductus venosus, disappears over the next few weeks, usually by 16 weeks; however, in 5% of cases, it may indicate the presence of a congenital heart defect. In this connection, it is recommended to undergo 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 of this type of ultrasound examination.
Of course, screening for the first trimester is not limited to the identification of ultrasound markers that increase the risk of having a baby with chromosomal abnormalities such as Down, Edwards, Patau, Turner and Triploidy Syndromes. In this period, developmental anomalies such as exencephaly and acrania, malformations of the limbs and sirenomelia, omphalocele and gastroschisis, megacystis and c-m prune belly, an anomaly of the body stem can also be diagnosed, suspect c-m Dandy-Walker and Spina bifida when changing the size of the IV ventricle, anorectal atresia when pelvic translucency is detected (pelvic translucency). And that's not all. I will try in the future to talk about the listed anomalies and developmental defects.
In conclusion, a few words about the procedure for the first trimester screening 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 are certified by this organization. The Fetal Medicine Foundation (FMF), headed by Professor Kipros Nikolaides, is engaged in research in the field of fetal medicine, diagnosis of fetal anomalies, diagnosis and treatment of various complications of pregnancy. Certified specialists and centers receive software developed by FMF for calculating the risk of fetal chromosomal pathology based on ultrasound and biochemical screening data. To obtain a certificate for performing ultrasound examination in 11-13 (+6) weeks, it is necessary to complete theoretical training on a course supported by FMF; undergo practical training at an accredited FMF center; provide FMF with ultrasound photographs demonstrating the measurement of fetal TVP, visualization of the nasal bones, Doppler blood flow in the ductus venosus and tricuspid valve according to the criteria developed by the FMF.
After filling out and signing numerous documents and consents at the registry, you will be invited to the ultrasound office, 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 from the chorion, uterine walls and ovaries.
After the research, you will be given a conclusion in duplicate and photos of your baby (or babies). You keep one copy of the conclusion, 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 the data of ultrasound and biochemistry, special software will calculate the individual risk of fetal chromosomal pathology and in 1-2 days you will receive a result, which will indicate the individual risks for the main CA. If you wish, the result can be received by e-mail.
In case of obtaining results with a low risk of major CA, you will be recommended to repeat the ultrasound scan at 19-21 weeks of pregnancy. If the risk turns out to be high, then remember that this is the result of a screening study, and not a diagnosis. An accurate diagnosis will require a consultation with a geneticist and diagnostic methods such as chorionic biopsy or amniocentesis for 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 the invasion of taking blood from the vein of a pregnant woman) - Non-invasive prenatal test.
I bring to your attention a table of pregnancy outcomes with an increase in TBP:
As you can see, even with very large TBI, about 15% of babies can be born healthy, but it is much more likely that the fetus will have CA or major developmental abnormalities.
Preparation for research
Biochemical screening is performed on an empty stomach (4-6 hours of hunger). More often, ultrasound and biochemistry are carried out on the same day, in my opinion, this is very convenient, but if you suddenly ate recently, then you can only undergo an ultrasound scan, and donate blood on another day, the main thing is no later than the full 13 weeks of pregnancy. No special preparation is required for an ultrasound scan, but an overflowing 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. Often, 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 treat with understanding.
That's all, see you in 2 weeks!
Pregnancy is a very important stage in the life of any woman. Each expectant mother begins to take care of the health of her baby already at the moment when he is in the womb. Modern medicine makes it possible to monitor the condition of the fetus through examination by a specialist, analyzes, and various diagnostic methods.
And if everyone knows about ultrasound as a mandatory procedure, then dopplerometry often remains a blank spot. Ignorance usually leads to the fact that the woman refuses this type of diagnosis. What is it really? Is it necessary to do dopplerometry? In what trimester should this additional examination be done? And how to decipher the obtained indicators?
What is dopplerometry?
Doppler ultrasound is a special type of ultrasound diagnostics that allows scanning and detailed assessment of vascular blood flow in both the baby and the mother's uterus.
The study, like the usual ultrasound, is based on the ability of ultrasound to be reflected from tissues, but in one caveat - the ultrasonic wave reflected from moving bodies has the ability to change the frequency of natural oscillations, and the sensor receives these waves with already changed purity.
The equipment decodes the received data - and a color image is obtained.
This diagnostic method is completely safe for the health of the baby and mother, has a high information content, is quite accessible, does not have side effects, is simple and reliable.
Dopplerometry
The procedure is not much different from a conventional ultrasound examination. The patient needs to expose her belly, lie on the couch on her back and relax. Then the diagnostician smears the abdomen and a special sensor with a special gel to improve the ultrasound conductivity, applies it to the woman's body and guides it over the skin, tilting it at different angles as needed.
The difference from a conventional ultrasound is the "picture" obtained with the help of the study - if traditionally on the monitor you can see a black and white incomprehensible image, then, and blue ones - the blood flow from the sensor. The brighter the color on the screen, the more intense the movement of blood flow.
At the end of the study, the specialist draws up a conclusion based on the analysis of the data obtained and attaches a snapshot, if required. It is worth paying attention to the fact that the diagnostician makes a diagnosis only on the basis of his own research, and the attending physician - taking into account the totality of all examination methods.
Analyzed indicators
Traditionally, the following Doppler indicators are distinguished, according to which the specialist draws up a conclusion:
- IR (Resistive Index): The difference between the highest and lowest velocity is divided by the highest recorded blood flow velocity.
- PI (pulsation index): the difference between the highest and lowest speeds is divided by the average rate of blood flow per cycle.
- SDO (systolic-distal ratio): the maximum blood flow velocity at the time of cardiac contraction is divided by the speed during the "rest" of the heart.
Doppler standards are usually divided by week, the indicators can be viewed in the tables below.
Table No. 1. Norms of IR for the uterine artery.
Table 2. Norms of the LMS for the umbilical artery.
Table 3. Norms of IR for the umbilical artery.
Table No. 4. Standards of the LMS for the aorta.
The LMS in the uterine artery should be close to 2.
The PI in the uterine artery is ideally 0.4-0.65.
It is worth noting that the greatest importance is attached, because at this time any deviation from the norm can be fatal, and medical assistance in other cases should be provided immediately.
Help in reading the conclusion
Very often it is quite difficult to understand the numbers, but even comparing the obtained indicators with the variants of the norm, the patients ask the question - what does this mean and what does it threaten? To answer these questions you need.
Doppler sonography of fetal hypoxia
High indicators of LMS and IR in the arteries of the uterus probably indicate hypoxia.... Increased indicators of IR and LMS in the umbilical cord proves the presence of gestosis and vascular pathology. High numbers of LMS and IR in the aorta also emphasize the abnormal state of the child in the uterus, often in this case, the baby needs to be provided with medical assistance. Increased indicators of IR and LMS in the umbilical artery and aorta of the fetus usually indicate Rh-conflict, overmaturity of the child or the presence of diabetes mellitus in the mother.
Low rates of IR and LMS also indicate a danger to the child's life.... Usually this is a consequence of a low, which affects only the most necessary organs of the baby. To stabilize the condition, urgent medical intervention is also required, otherwise a lethal outcome is likely.
The indicators for multiple pregnancies are especially important, because doctors are interested in whether children receive oxygen from their mother in the same way. The indicators of LMS and IR in the umbilical artery will be higher in the child who receives less oxygen as a result.
Reasons for the survey
This type of examination allows doctors to monitor, as well as in the fetal aorta, cerebral and carotid arteries.
This type of ultrasound diagnostics may seem like a whim, but in fact, the optimal blood supply to the fetus, its oxygen supply, and hence the timely development of the child in the womb depend on the correct blood flow.
Pathologies detected in time using this method are the key to preserving the life of the child. Sometimes, to stabilize the condition of the fetus, it is enough to adjust the lifestyle or taking certain medications, in some cases the intervention of medical personnel may be required. But be that as it may, it is only possible to learn about vascular anomalies of this kind.
Of course, dopplerometry is not an obligatory diagnostic method during pregnancy. A woman can do ultrasound diagnostics with dopplerometry at her own request a couple of times before the birth of the child. However, there are cases in which the attending physician strongly recommends this particular method of assessing the condition of the fetus.
Diagnostic indications
Ultrasound of twins 10 weeks
First of all, the specificity of this type of examination does not allow it to be carried out, because it is at this time that the placenta is finally formed. In the early stages, such research is simply not informative. Usually, doctors recommend diagnosing this method for the first time (in the second trimester).
But there are also certain indications in which dopplerometry becomes a mandatory step. These are usually the following:
- Early pregnancy.
- The mother-to-be is old-born.
- Low water.
- Polyhydramnios.
- An ultrasound scan previously diagnosed an umbilical cord wrapped around the baby's neck.
- Slow fetal development.
- Any suspicion of malformations of the child.
- Infectious diseases of the urogenital system of the mother.
- Certain chronic maternal diseases such as diabetes mellitus, hypertension, lupus.
- The presence of multiple embryos in the uterus.
- An interrupted previous pregnancy (reasons: spontaneous miscarriage or missed pregnancy).
- Malformations in previous children, if any.
- Abdominal trauma of any nature.
- Rh factor conflict between mother and fetus.
Preparation for the examination
Since such an ultrasound is traditionally performed so as not to harm the baby, then special preparation from a pregnant woman is not required. It is enough to carry out the simplest hygiene procedures, as well as visit the diagnostician's office in a state of calm.
It is important to note that the bladder does not need to be filled, and it is also forbidden to take medications unless the circumstances require it.
Is this diagnostic method dangerous?
It has long been proven by experts.
First, ultrasound cannot harm either the mother or the baby.
Secondly, ultrasound examination is not fraught with any consequences for the human body.
Thirdly, the abdominal method excludes possible injuries, as it is as painless and accurate as possible.
Fourthly, Doppler measurement itself is possible due to a technological breakthrough and depends on the capabilities of the equipment in the diagnostic room, and not on any special manipulations of the doctor, therefore it is just as safe.
Pathology
Traditionally, such an ultrasound scan makes it possible to track the following anomalies:
- Oxygen starvation of the fetus.
- Insufficient oxygen intake by one of the children with multiple pregnancies.
- Vascular pathology.
- Developmental deviation in a child.
What to do after receiving the opinion?
Comparison of the obtained indicators with the figures of the norm and self-decoding are useful skills, especially if you urgently want to know the result of the examination, because we are talking about the health of the child. But in no case can we assume that this information will be sufficient. Moreover, there is no guarantee that you will be able to do this correctly.
The conclusion of an ultrasound scan with a preliminary diagnosis must be shown to the attending gynecologist, and only he can and has the right to draw final conclusions.
It is very important, when reading on your own, not to take any medications without consulting a doctor!
Is there a chance of medical error?
Since ultrasound diagnostics is performed by a person, the human factor cannot be excluded. But dopplerometry is still done "in color", and the probability of an error here is extremely small, especially since the examination is performed by a qualified experienced specialist. Incorrect results can only be obtained with faulty hardware. If the patient has any suspicions, she can always do an ultrasound scan in another diagnostic room.
Doppler ultrasound is a very important type of ultrasound diagnostics with advanced capabilities due to the technological revolution in medicine. Such a study also allows the aorta, and hence the condition of the unborn child, which is not only useful, but also extremely necessary in some cases. Sometimes only thanks to dopplerometry it is possible to detect extremely severe pathologies and react in time to save the life of the baby and even the mother.
Simplicity, accessibility, safety and information content are what characterizes this type of ultrasound. Pregnant women should not underestimate the value of this method. Even in the absence of direct indications for this method, diagnostics should be done by Doppler at least several times during the entire period of pregnancy in order to independently verify the health of your child.
1Quantitative indicators of blood flow velocity in the venous duct of the fetus in different phases of the cardiac cycle in healthy women with 11 to 14 weeks of pregnancy were studied by means of Doppler sonography. At the same time, the concentration in the blood of a pregnant woman of plasma protein A (PAPP-A) and free beta-subunit of chorionic gonadotropin (beta-hCG) was taken into account. It was found that in healthy pregnant women, the linear velocity of blood flow in the venous duct of the fetus has a significant (almost two-fold) variation range, which excludes the dependence of these indicators on the gestational age in weeks and on the chorionic thickness. A weak negative correlation was established between the content of specific proteins and pregnancy hormones (PAPP-A and beta-HCG) in a woman's blood and the relative carbon-dependent parameters of blood flow in the fetal venous duct - the ratio of blood flow velocities in systole and early diastole, as well as the venous velocity index and the index vein resistance. The revealed dependence gives grounds to use the carbon-dependent parameters of the curves of blood flow rates 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
blood flow curves
1. Altynnik N.A. The value of 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 // Bulletin of Volgograd Med. university. - 2012. - No. 4. - P. 66–68.
2. Lisyutkina E.V. Diagnostic value of Doppler sonography of blood flow in the venous duct of the fetus at various stages of pregnancy: author. dis. ... Cand. honey. sciences. - M., 2013 .-- 18 p.
3. The procedure for the provision of medical care in the field of "obstetrics and gynecology (except for the use of assisted reproductive technologies)". Order of the Ministry of Health of the Russian Federation of November 01, 2012 No. 572n.
4. Radzinsky V.E. Obstetric aggression. - M .: Publishing house of the journal Status Praesens, 2011 .-- 618 p.
5. Practical recommendations of ISUOG: the use of ultrasound Doppler technologies in obstetrics. International Society of Ultrasound Diagnostics in Obstetrics and Gynecology (ISUOG) / A. Bride, G. Acharya, C. M. Bilardo et al. // Ultrasound 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. - P. 860–865.
The urgency 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 outcome of pregnancy and childbirth. Over the past decade, hospitals have been ubiquitously 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 standard screening ultrasound examination of pregnant women for the early formation of high-risk groups. Among the Doppler parameters determined in the first trimester of pregnancy, the study of the curves of blood flow rates (CVC) in the venous duct of the fetus has attracted the greatest attention of researchers. The high predictive 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 pregnancies. But these studies concerned only the qualitative study of the CSC (registration of retrograde or unidirectional blood flow). The quantitative normative parameters of the blood flow velocity in the venous duct of the fetus at the turn of the first and second trimesters of pregnancy in different phases of the cardiac cycle remain unknown to date. This limits the possibilities of using this method for predicting other types of obstetric pathology. The existing problem indicated the direction of the research.
The aim of the work is to determine the normative parameters of the fetal blood flow rates at 11-14 weeks of gestation.
Material and research methods
The object of the study consisted of 72 somatically healthy women with a physiological course of singleton pregnancy, having from 11 weeks. + 0/7 days to 13 weeks + 6/7 days of gestation. Study inclusion criteria:
a) age from 18 to 35 years old;
b) pregnancy from 11 to 14 weeks;
c) bearing one fruit;
d) the location of the chorion in the bottom or along the lateral walls of the uterus;
e) the absence of extragenital pathology at the stage of sub- and decompensation;
f) 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 using a Voluson E8 ultrasound machine (USA), in compliance with the ALARA principle (As Low As Reasonably Achieveble) - "As Low As Reasonably Achieveable", i.e. using the most prudently low power output. Registration of blood flow in the venous duct of the fetus was carried out by specialists who have the appropriate Certificate of the Fetal Medicine Foundation. The blood flow velocity was measured in systole (S), diastole (E) of the ventricles of the heart, as well as during contraction of the vestibule of the heart, i.e. in late diastole (A).
The ratios of the phase velocities of blood flow (S / E and S / A) were calculated, as well as the carbon-independent indices - the vein resistance index (IVR) and the venous velocity index (VVI). 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 of "obstetrics and gynecology (excluding the use of assisted reproductive technologies)". In addition to the data of the clinical examination of the patients, the study took into account the content of plasma protein A (PAPP-A) and free beta-subunit of chorionic gonadotropin (beta-hCG) in the blood of women on the day of examination, 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 their discussion
The data obtained indicate that the blood flow velocity in the ductus venosus 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 were determined by more than a twofold discrepancy in the recorded parameters. At the same time, the linear parameters of blood circulation did not depend either on the gestational age in weeks or on the chorionic thickness 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 curves of blood flow rates 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 velocities in systole and early diastole (S / E) in healthy pregnant women were less variable - the discrepancy in indicators was 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 obtained data are preliminary, nevertheless, they show that the curves of blood flow rates in the venous duct of the fetus in the early stages of pregnancy can be subjected not only to qualitative analysis (detection of retrograde and zero blood flow), but can also be presented as numerical values for early prediction. gestational complications.
Reviewers:Agarkova LA, MD, DSc, 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, FPK and APS, Siberian State Medical University, Ministry of Health of the Russian Federation, Tomsk.
The work was received on 12.02.2015.
Bibliographic reference
Mikheenko G.A., Yuriev S.Yu., Korotkova Yu.Yu. PHASE PARAMETERS OF BLOOD FLOW RATE IN THE VENOUS FETAL FLOW 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: 13.12.2019). We bring to your attention the journals published by the "Academy of Natural Sciences"
Prenatal screening examination of the first trimester consists of two procedures: ultrasound diagnostics and blood tests for the possibility of genetic abnormalities of the fetus. There is nothing wrong with these events. The data obtained by performing an ultrasound procedure and a blood test is compared with the norm for this period, which allows you to confirm the good or bad condition of the fetus and determine the quality of the gestation process.
For the expectant mother, the main task is to maintain a good psycho-emotional and physical condition. It is also important to follow the instructions of the obstetrician-gynecologist leading the pregnancy.
Ultrasound is only one study of the screening complex. To obtain complete information about the health of the baby, the doctor must check the blood of the future woman in labor for hormones, evaluate the result of a general analysis of urine and bloodStandards for ultrasound diagnostics I screening
In the process of carrying out the first prenatal screening in the first trimester, the ultrasound diagnostics doctor pays special attention to the anatomical structures of the fetus, specifies the gestational age (gestation) on the basis of fetometric indicators, comparing it with the norm. The most carefully evaluated criterion is the thickness of the collar space (TVP), because this is one of the main diagnostically significant parameters, which makes it possible to identify genetic diseases of the fetus during the first ultrasound procedure. In chromosomal abnormalities, the collar space is usually enlarged. Weekly TVP rates are shown in the table:
When conducting ultrasound screening of the first trimester, the doctor pays special attention to the structure of the facial structures of the fetal skull, the presence and parameters of the nasal bone. For a 10-week period, it is already quite clearly defined. At 12 weeks old - its size in 98% of healthy fetuses is from 2 to 3 mm. The maxillary bone size of the baby is assessed and compared with the norm. a noticeable decrease in the parameters of the jaw in relation to the norm indicates trisomy.
On ultrasound 1 screening, the fetal heart rate (heart rate) is recorded and is also compared with the norm. The indicator depends on the gestational age. Weekly heart rate rates are shown in the table:
The main fetometric indicators at this stage during the ultrasound procedure are the coccygeal-parietal (CTE) and biparietal (BPD) sizes. Their norms are given in the table:
| Fetal age (week) | Average CTE (mm) | Medium BPD (mm) |
|---|---|---|
| 10 | 31-41 | 14 |
| 11 | 42-49 | 13-21 |
| 12 | 51-62 | 18-24 |
| 13 | 63-74 | 20-28 |
| 14 | 63-89 | 23-31 |
The first screening provides for an ultrasound assessment of blood flow in the venous (Arantia) duct, since in 80% of cases of its violation, the child is diagnosed with Down syndrome. And only 5% of genetically normal fetuses show such changes.
Starting from the 11th week, it becomes possible to visually recognize the bladder during an ultrasound scan. At the 12th week, at the first ultrasound screening, its volume is assessed, since an increase in the size of the bladder is another evidence of the threat of the development of trisomy (Down) syndrome.
It is best to donate blood for biochemistry on the same day as the ultrasound screening. Although this is not a requirement. Blood sampling is carried out on an empty stomach. The analysis of biochemical parameters, which is carried out in the first trimester, is aimed at identifying the degree of threat of the occurrence of genetic diseases in the fetus. For this, the following hormones and proteins are determined:
- pregnancy-associated plasma protein-A (PAPP-A);
- free hCG (beta component).
These indicators depend on the week of pregnancy. The range of possible values is quite wide and correlates with the ethno-content of the region. In relation to the average-normal value for a given region, the level of indicators fluctuates within the following limits: 0.5-2.2 MoM. When calculating the threat and decoding the data, not just the average value is taken for analysis, all possible corrections for the anamnestic data of the expectant mother are taken into account. This adjusted MoM allows to more fully determine the threat of the development of fetal genetic pathology.
A blood test for hormones is necessarily carried out on an empty stomach and is often prescribed on the same day as an ultrasound scan. Due to the presence of standards for the hormonal characteristics of the blood, the doctor can compare the test results of a pregnant woman with the norms, identify a lack or excess of certain hormones HCG: an assessment of risk values
In terms of information content, free hCG (beta component) is superior to total hCG as a marker of the risk of genetic abnormalities in the fetus. The rates of beta-hCG with a favorable course of gestation are shown in the table:
This biochemical indicator is one of the most informative. This applies to both the identification of genetic pathology and the marking of the course of the gestation process and the changes occurring in the body of a pregnant woman.
Pregnancy-Associated Plasma Protein-A Rates
This is a specific protein that the placenta produces throughout the gestational period. Its growth corresponds to the period of development of pregnancy, has its own standards for each period. If there is a decrease in the level of PAPP-A in relation to the norm, this is a reason to suspect a threat of the development of a chromosomal abnormality in the fetus (Down and Edwards disease). The norms of PAPP-A indicators in normal gestation are shown in the table:
However, the level of protein associated with pregnancy loses its informative value after the 14th week (as a marker of the development of Down's disease), since after this period its level in the blood of a pregnant woman carrying a fetus with a chromosomal abnormality corresponds to a normal indicator - as in the blood of a woman who has healthy pregnancy.
Description of the results of the first trimester screening
To evaluate the results of the 1st screening, each laboratory uses a specialized computer product - certified programs that are configured for each laboratory separately. They make a basic and individual calculation of the indicators of the threat for the birth of a baby with a chromosomal abnormality. Based on this information, it becomes clear that all tests are best done in one laboratory.
The most reliable prognostic data are obtained during the first prenatal screening in the first trimester in full (biochemistry and ultrasound). When decoding the data, both indicators of biochemical analysis are considered in combination:
low values of protein-A (PAPP-A) and increased beta-hCG - a threat of the development of Down's disease in a child;
low levels of protein-A and low beta-hCG - a threat of Edwards disease in a baby.
There is a fairly accurate procedure to confirm a genetic abnormality. However, this is an invasive test that can be dangerous for both the mother and the baby. To clarify the need to apply this technique, the data of ultrasound diagnostics are analyzed. In the case of the presence of echo signs of a genetic abnormality on an ultrasound scan, the woman is advised to undergo invasive diagnostics. In the absence of ultrasound data indicating the presence of chromosomal pathology, the expectant mother is recommended to repeat the biochemistry (if the period has not reached 14 weeks), or wait for the indications of the 2nd screening study in the next trimester.
Chromosomal abnormalities in fetal development are most easily detected using a biochemical blood test. However, if the ultrasound did not confirm the fears, it is better for the woman to repeat the study after a while, or wait for the results of the second screening Risk assessment
The information received is processed by a specially created program for solving this problem, which calculates the risks and gives a fairly accurate forecast regarding the threat of the development of fetal chromosomal anomalies (low, threshold, high). It is important to remember that the resulting interpretation of the results is only a forecast, not a final verdict.
In each country, the quantitative expression of the levels varies. We consider a high level to be less than 1: 100. This ratio means that for every 100 births (with similar test results), 1 child is born with a genetic disorder. This degree of threat is considered an absolute indication for invasive diagnostics. In our country, the threshold level includes the threat of having a baby with developmental defects in the range from 1: 350 to 1: 100.
Threat threshold means that a baby can be born sick with a risk of 1: 350 to 1: 100. At a threshold level of threat, a woman is sent to an appointment with a geneticist, who provides a comprehensive assessment of the data obtained. The doctor, having studied the parameters and anamnesis of the pregnant woman, defines her in the risk group (with its high degree or low). Most often, the doctor recommends waiting until the second trimester screening study, and then, having received a new threat calculation, again come to the appointment to clarify the need for invasive procedures.
The information described above should not scare expectant mothers, nor do you need to refuse to undergo a first trimester screening. Since most pregnant women have a low risk of carrying a sick baby, they do not need additional invasive diagnostics. Even if the examination showed the poor condition of the fetus, it is better to find out about this in a timely manner and take appropriate measures.
If research has identified a high risk of having a sick child, the doctor must honestly convey this information to the parents. In some cases, invasive research helps to clarify the health situation of the fetus. With unfavorable results, it is better for a woman to terminate the pregnancy at an early stage in order to be able to carry a healthy child If the results are unfavorable, what should I do?
If it so happened that the analysis of the indicators of the first trimester screening examination revealed a high degree of threat of the birth of a child with a genetic abnormality, first of all, you need to pull yourself together, since emotions negatively affect the bearing of the fetus. Then start planning further actions.
First of all, it is hardly worth the time and money to be re-screened in another laboratory. If the risk analysis shows a ratio of 1: 100, there is no time to hesitate. You need to immediately contact a geneticist for advice. The less time wasted, the better. With such indicators, most likely, a traumatic method of data confirmation will be prescribed. At 13 weeks, this will be an analysis of the chorionic villus biopsy sample. After 13 weeks, it may be recommended to have a cord or amniocentesis. Chorionic villus biopsy analysis gives the most accurate results. The waiting period for results is about 3 weeks.
In case of confirmation of the development of chromosomal abnormalities of the fetus, the woman will be recommended to artificially terminate the pregnancy. The decision is definitely up to her. But if a decision is made to terminate the pregnancy, then the procedure is best carried out at 14-16 weeks.
Dopplerometry during pregnancy is a modern diagnostic method using ultrasound, which allows an objective and complete examination of the blood circulation of the fetus, placenta and uterus. According to the state of the circulatory system, it is possible to assess the condition of the fetus, the speed of its development - whether the baby suffers from a lack of oxygen, as well as possible pathological changes. Fetal Doppler is the only technique that can show the exact location of vascular pathology (in the uterus, umbilical cord or placenta).
Doctor's consultation based on test results or ultrasound - 500 rubles. (at the request of the patient)
Why and when to carry out Doppler measurements during pregnancy
Today, vascular disease is one of the most common problems in medical practice. Timely diagnosis makes it possible to identify such pathologies at an early stage of development, and at the same time many factors that can cause the development of circulatory disorders.
The value of the procedure lies in its high information content, due to which the doctor is able to identify not only the already developed pathology, but also almost imperceptible preclinical symptoms of the disease. The procedure is prescribed after the complete formation of the placenta - not earlier than 18 weeks, more often at 32-34 weeks as a routine check.
If there is even a slight suspicion of fetal developmental disorders, an ultrasound scan with a Doppler is performed at any time. Doppler is done in conjunction with , while for a pregnant woman, the procedure does not differ from the classical ultrasound examination.
Method essence
This method of studying the circulatory system is based on the application of the Doppler effect.
The examination uses the same ultrasound as for a conventional ultrasound examination. The difference lies in the special Doppler sensor and the interpretation of the data obtained. During the study, ultrasonic waves are recorded, reflected not from static tissues, but from moving objects - blood cells, as a result of which the frequency of the reflected rays changes greatly in comparison with the studied ones. The machine processes the received data and creates a two-dimensional color image. Thanks to this, it is possible to assess the speed and direction of blood flow, anatomy and vascular patency.
The duration of Doppler sonography is 20 - 40 minutes. It has no contraindications, no complications, no negative effects on the body. The study is completely painless and safe.
Indications
Gynecologists recommend to undergo a Doppler examination 1-2 times during pregnancy together with ... If there are problems, the fetal Doppler needs to be done as soon as possible. Basically, dopplerometry is prescribed when the size of the fetus does not match the gestational age. Also, the procedure is carried out in the following cases:
- complications in carrying a child;
- placental insufficiency;
- the mother has chronic and severe diseases (diabetes mellitus, hypertension, anemia, systemic diseases);
- Rh-conflict between a pregnant woman and a child;
- multiple pregnancy;
- non-immune dropsy of the fetus;
- incorrect position of the fetus in the uterus;
- premature maturation of the placenta;
- entanglement of the baby's neck with the umbilical cord, suspicion of hypoxia;
- pronounced oligohydramnios / polyhydramnios;
- gestosis (late toxicosis, accompanied by a deterioration in the functioning of the kidneys, blood vessels and the brain - protein appears in the urine, blood pressure rises);
- trauma abdomen in a pregnant woman;
- chromosomal abnormalities of the infant;
- the fetus moves less than usual or the movement is not felt at all;
- unsatisfactory results of cardiotocography;
- complications in carrying a previous pregnancy (premature birth, miscarriage, etc.).
Also, an ultrasound of the fetus with a Doppler must be done in cases where the mother is not 20 years old or she is more than 35 years old.
What does fetal dopplerometry reveal?
Doppler helps to timely identify fetal hypoxia and avoid problems even before the child is in danger, or to minimize negative consequences. With its help, the doctor can find out the reasons for entanglement with the umbilical cord and see how many times and how tightly the baby's neck is entwined. Without this vital information, specialists will not be able to choose the right tactics for childbirth, which jeopardizes the health and life of the child.
Also, using the Doppler, you can see:
- the state and rhythm of the fetal heart at rest and movement;
- the condition of the heart valves of the main blood vessels, arteries and veins;
- the speed and volume of blood flow in the peripheral circulatory system;
- blood circulation in the umbilical cord and placenta;
- the state of the circulatory system, heart and kidneys of the pregnant woman.
The information obtained allows the doctor to assess:
- patency and condition of the vascular bed, the presence of deviations that block the blood flow of the fetus;
- saturation with blood and nutrients of all tissues of the child;
- patency and condition of the umbilical cord, entanglement of the baby's neck;
- the efficiency of the placenta;
- condition and work of the circulatory system of a woman during pregnancy.
Preparation and features of the ultrasound of the fetus with Doppler
The procedure does not require any preparatory measures: neither the diet, nor the fullness of the bladder and stomach affect the examination results. The only recommendation is to take a break from eating for a couple of hours before the examination.
The pregnant woman needs to take the following with her: the direction and results of past analyzes and examinations (ultrasound, CTG, ECG), the exchange card of the pregnant woman. Paper napkins and a disposable diaper or towel are not needed - everything is provided free of charge in our clinic.
Doppler technique is similar to transabdominal ultrasound. The woman lies down on the couch with her back and exposes her belly. The doctor applies a special gel to the area under study to improve the permeability of ultrasonic waves and then guides the transducer over it, simultaneously examining the data obtained on the monitor. The interpretation of the results is issued to the woman on the same day.
Doppler testing during pregnancy can be done in several ways:
- Ultrasonic Doppler - used to assess the direction, intensity, nature of blood flow in the vessels.
- Duplex study - differs from the previous method in greater accuracy and informational content. It is used to assess the blood flow of blood vessels and their anatomy.
- Color mapping - the state of even the smallest vessels and their patency is color coded.
Deciphering the results of fetal dopplerometry
Assessment of the state of blood supply using Doppler is formed on the basis of the following indicators:
- Systolic-diastolic ratio - the ratio of the maximum and minimum blood flow velocity;
- Index resistance - the ratio of the difference between the maximum and minimum blood flow velocity to the maximum during the period of compression;
- Pulsating index - the ratio of the difference between the maximum and minimum blood flow velocity to the average velocity over a complete heart cycle.
Fetal Doppler: weekly rate and prognosis for deviations
In order for the interpretation of the results to pass correctly and all deviations were identified, it is necessary to compare the data obtained with the standard values, taking into account the gestational period.
Indicators of the norm of the resistance index of the uterine arteries
Gestational period (weeks) | Average index of IR of the uterine arteries | Possible fluctuation range |
0,52 | 0,37 – 0,7 |
|
0,51 | 0,36 – 0,69 |
|
0,36 – 0,68 |
||
0,36 – 0,68 |
||
0,35 – 0,67 |
||
0,49 | 0,35 – 0,66 |
|
0,49 | 0,35 – 0,65 |
|
0,48 | 0,34 – 0,64 |
|
0,48 | 0,34 – 0,64 |
|
0,47 | 0,34 – 0,63 |
|
0,46 | 0,34 – 0,62 |
|
0,46 | 0,34 – 0,61 |
|
0,45 | 0,34 – 0,61 |
|
0,45 | 0,34 – 0,59 |
|
0,45 | 0,34 – 0,59 |
|
0,45 | 0,33 – 0,58 |
|
0,44 | 0,33 – 0,58 |
|
0,44 | 0,33 – 0,57 |
|
0,44 | 0,33 – 0,57 |
|
0,43 | 0,33 – 0,57 |
|
0,43 | 0,32 – 0,57 |
|
0,43 | 0,32 – 0,56 |
Standard indicators of the pulsation index of the uterine arteries
Gestational period (weeks) | Average PI of the uterine arteries | Possible fluctuation range |
1,54 | 1,04 – 2,03 |
|
1,47 | 0,98 – 1,96 |
|
1,41 | 0,92 – 1,9 |
|
1,35 | 0,86 – 1,85 |
|
0,81 – 1,79 |
||
1,25 | 0,76 – 1,74 |
|
0,71 – 1,69 |
||
1,16 | 0,67 – 1,65 |
|
1,12 | 0,63 – 1,61 |
|
1,08 | 0,59 – 1,57 |
|
1,05 | 0,56 – 1,54 |
|
1,02 | 0,53 – 1,51 |
|
0,99 | 0,5 – 1,48 |
|
0,97 | 0,48 – 1,46 |
|
0,95 | 0,46 – 1,44 |
|
0,94 | 0,44 – 1,43 |
|
0,92 | 0,43 – 1,42 |
|
0,92 | 0,42 – 1,41 |
|
0,91 | 0,42 – 1,4 |
|
0,91 | 0,42 – 1,4 |
|
0,91 | 0,42 – 1,4 |
|
0,92 | 0,42 – 1,41 |
The indicators of the right and left uterine artery can be different. The main thing is that both indicators do not go beyond the normal range. If both indicators do not correspond to the norm, this indicates a violation of the uteroplacental circulation. If one indicator - on the asymmetry of the uteroplacental blood flow
It is important to note that at 18-21 weeks, deviations of indicators may be observed due to an incomplete adaptive physiological process of cytotrophoblast invasion. In this case, fetal dopplerometry should be repeated in 2-3 weeks.
Standard indicators of the systolic-diastolic ratio in the fallopian tubes
Doppler rate: umbilical arteries
Standard values of the umbilical cord artery resistance index:
Gestational period (weeks) | Average index of IR of umbilical arteries | Possible fluctuation range |
0,74 | 0,63 – 0,84 |
|
0,73 | 0,62 – 0,83 |
|
0,72 | 0,61 – 0,82 |
|
0,71 | 0,6 – 0,82 |
|
0,59 – 0,81 |
||
0,69 | 0,58 – 0,8 |
|
0,68 | 0,58 – 0,79 |
|
0,67 | 0,57 – 0,79 |
|
0,66 | 0,56 – 0,78 |
|
0,65 | 0,55 – 0,78 |
|
0,64 | 0,54 – 0,77 |
|
0,63 | 0,53 – 0,76 |
|
0,62 | 0,52 – 0,75 |
|
0,61 | 0,51 – 0,74 |
|
0,49 – 0,73 |
||
0,59 | 0,48 – 0,72 |
|
0,58 | 0,46 – 0,71 |
|
0,57 | 0,44 – 0,7 |
|
0,56 | 0,43 – 0,69 |
|
0,55 | 0,42 – 0,68 |
|
0,54 | 0,41 – 0,67 |
|
0,53 | 0,4 – 0,66 |
Standard values of the pulsation index of the umbilical arteries:
Gestational period (weeks) | Average PI of the umbilical arteries | Possible fluctuation range |
1,72 | 1,53 – 1,9 |
|
1,62 | 1,45 – 1,78 |
|
1,45 | 1,25 – 1,65 |
|
1,35 | 1,18 – 1,51 |
|
1,35 | 1,17 – 1,52 |
|
1,25 | 1,09 – 1,41 |
|
1,12 | 0,96 – 1,27 |
|
1,15 | 0,98 – 1,33 |
|
1,01 | 0,86 – 1,16 |
|
1,01 | 0,86 – 1,16 |
|
1,05 | 0,87 – 1,23 |
|
1,03 | 0,88 – 1,17 |
|
0,95 | 0,76 – 1,13 |
|
0,85 | 0,71 – 0,99 |
|
0,84 | 0,67 – 1,1 |
|
0,84 | 0,59 – 0,93 |
|
0,83 | 0,58 – 0,99 |
|
35 — 37 | 0,81 | 0,57 – 1,05 |
38 — 41 | 0,74 | 0,37 – 1,08 |
Obtaining zero and reverse values of diastolic blood flow is considered a pathology. This indicates the critical condition of the fetus, the death of which will occur in 2-3 days. In this case, a caesarean section is immediately prescribed (if the gestational period is more than 28 weeks) to save the life of the baby.
Standard values of the systolic-diastolic ratio of the umbilical arteries:
Violation of blood flow in the umbilical cord entails a delay in the development of the child.
Doppler ultrasound rates: fetal middle cerebral artery
Gestational period (weeks) | Average PI in the middle cerebral artery | Possible fluctuation range |
1,83 | 1,36 – 2,31 |
|
1,87 | 1,4 – 2,34 |
|
1,91 | 1,44 – 2,37 |
|
1,93 | 1,47 – 2,4 |
|
1,96 | 1,49 – 2,42 |
|
1,97 | 1,51 – 2,44 |
|
1,98 | 1,52 – 2,45 |
|
1,99 | 1,53 – 2,45 |
|
1,99 | 1,53 – 2,46 |
|
1,99 | 1,53 – 2,45 |
|
1,98 | 1,52 – 2,44 |
|
1,97 | 1,51 – 2,43 |
|
1,95 | 1,49 – 2,41 |
|
1,93 | 1,46 – 2,39 |
|
1,43 – 2,36 |
||
1,86 | 1,4 – 2,32 |
|
1,82 | 1,36 – 2,28 |
|
1,78 | 1,32 – 2,24 |
|
1,73 | 1,27 – 2,19 |
|
1,67 | 1,21 – 2,14 |
|
1,61 | 1,15 – 2,08 |
|
1,55 | 1,08 – 2,01 |
Maximum velocity in the fetal middle cerebral artery:
Gestational period (weeks) | Average indicator | Possible fluctuation range |
19,7 | 16,7 – 23 |
|
21,8 | 18,1 — 26 |
|
23,9 | 19,5 — 29 |
|
20,8 — 32 |
||
28,2 | 22,2 – 35 |
|
30,3 | 23,6 – 38,1 |
|
32,4 | 24,9 – 41,1 |
|
34,6 | 26,3 – 44,1 |
|
36,7 | 27,7 – 47,1 |
|
38,8 | 29 – 50,1 |
|
40,9 | 30,4 – 53,1 |
|
43,1 | 31,8 – 56,1 |
|
45,2 | 33,1 – 59,1 |
|
47,3 | 34,5 – 62,1 |
|
49,5 | 35,9 – 65,1 |
|
51,6 | 37,2 – 68,2 |
|
53,7 | 38,6 – 71,2 |
|
55,8 | 40 – 74,2 |
|
41,3 – 77,2 |
||
60,1 | 42,7 – 80,2 |
|
62,2 | 44,1 – 83,2 |
|
64,4 | 45,4 – 86,2 |
Standard values of the systolic-diastolic ratio in the middle cerebral artery:
Normal Fetal Doppler Readings: Fetal Aorta
Disturbances in the circulation of the fetal aorta can be detected only after 22-24 weeks of pregnancy.
Standard value of the fetal aortic pulsation index:
Gestational period (weeks) | Average PI of the fetal aorta | Possible fluctuation range |
1,79 | 1,49 – 2,16 |
|
1,79 | 1,49 – 2,16 |
|
1,79 | 1,49 – 2,17 |
|
1,49 – 2,18 |
||
1,49 – 2,19 |
||
1,81 | 1,49 – 2,2 |
|
1,81 | 1,49 – 2,21 |
|
1,82 | 1,5 – 2,22 |
|
1,83 | 1,5 – 2,24 |
|
1,82 | 1,51 – 2,25 |
|
1,81 | 1,51 – 2,26 |
|
1,81 | 1,52 – 2,28 |
|
1,53 – 2,29 |
||
1,53 – 2,31 |
||
1,79 | 1,54 – 2,32 |
|
1,79 | 1,55 – 2,34 |
|
1,79 | 1,55 – 2,35 |
|
1,92 | 1,56 – 2,36 |
|
1,93 | 1,57 – 2,38 |
|
1,94 | 1,57 – 2,39 |
|
1,94 | 1,57 – 2,4 |
|
1,95 | 1,58 – 2,41 |
Standard values of the fetal aorta resistance index:
Standard values of the systolic velocity of the fetal aorta:
Gestational period (weeks) | Average systolic rate | Possible fluctuation range |
26,88 | 12,27 – 44,11 |
|
28,87 | 14,1 – 46,28 |
|
30,52 | 15,6 – 48,12 |
|
31,95 | 16,87 – 49,74 |
|
33,23 | 18 – 51, 2 |
|
34,39 | 19 – 52,55 |
|
35,47 | 19,92 – 53,81 |
|
36,47 | 20,77 – 55,01 |
|
37,42 | 21,55 – 56,13 |
|
38,32 | 22,3 – 57,22 |
|
39,17 | 23,02 – 58,26 |
|
40,01 | 23,66 – 59,27 |
|
40,8 | 24,3 – 60,26 |
|
41,57 | 24,92 – 61,21 |
|
42,32 | 25,52 – 62,16 |
|
43,06 | 26,1 – 63,08 |
|
43,79 | 26,67 – 64,02 |
|
44,52 | 27,24 – 64,93 |
|
45,24 | 27,8 – 65,81 |
|
45,96 | 28,37 – 66,72 |
|
46,7 | 28,95 – 67,65 |
|
47,47 | 29,57 – 68,62 |
Standard values of the systolic-diastolic ratio of the fetal aorta:
Doppler rates during pregnancy: ductus venosus
The ductus venosus is not assessed using indices. An indicator of pathology is zero or negative blood flow values. Usually, similar values are obtained with fetal malnutrition, congenital heart disease, non-immune dropsy.
In the case when the blood circulation in the umbilical cord is in critical condition, but no blood flow abnormalities have been identified in the ductus venosus, it is possible to prolong gestation until the optimal time for delivery.
How will a gynecologist understand if there is fetal hypoxia?
The doctor compares the normal Doppler measurements with the result.
- An increase in IR and LMS in the uterine arteries is a sign that the baby is not getting enough oxygen. This will lead to a delay in development.
- An increase in Doppler indices for the umbilical artery is a sign of feto-placental insufficiency. This is a vascular pathology, so the fetus is already suffering. It is also a sign of preeclampsia.
- If the indicators of IR and LMS in the umbilical cords with multiple pregnancies differ, this indicates that one of the babies is experiencing hypoxia (transfusion syndrome).
- Excess LMS and IR in the aorta is a symptom of a child's poor health due to prolonged pregnancy, due to diabetes mellitus in a pregnant woman, in case of a conflict over the Rh factor, etc.
- A decrease in LMS and IR with Doppler measurements in the carotid and cerebral arteries is observed in extremely serious condition of the fetus, since in this case only the main organs that support life are supplied with blood. In such a situation, artificial childbirth should be carried out immediately.