Prenatal diagnosis - invasive methods. Invasive methods - obstetrics

Already by their name, invasive methods suggest a more serious nature of the indications for their implementation, since in themselves they are more traumatic and technically difficult to perform. And, most importantly, such methods are not always safe for the mother and fetus. On the other hand, the use of non-invasive methods is ubiquitous in the study of the health status of the expectant mother and child.

Invasive diagnostic methods during pregnancy

Amnioscopy - this invasive method during pregnancy is based on an assessment of the quantity and quality of amniotic fluid. Its implementation involves the introduction of a special device (endoscope) into the cervical canal, and through a visual assessment of the above data, a conclusion is made. A decrease in the amount of water and the detection of meconium elements in them are unfavorable diagnostic signs in assessing the further condition of the fetus. The technique for performing invasive methods during pregnancy is not too complicated. However, amnioscopy is only possible if the cervical canal can "miss" the instrument. This examination is technically possible at the end of pregnancy, when the cervix is ​​being prepared for childbirth and the cervical canal is partially opened.

Amniocentesis is a puncture of the amniotic cavity to collect amniotic fluid. Carrying out this diagnostic method during pregnancy is possible with the help of transabdominal access under ultrasound control of the manipulation being performed. The puncture is performed in the area of ​​the largest "pocket" of amniotic fluid, where there are no parts of the fetus and umbilical cord loops, avoiding possible trauma to the placenta. 10–20 ml of amniotic fluid are aspirated, depending on the goals of diagnosis. As a rule, this research method is used to diagnose congenital and hereditary diseases of the fetus, to more accurately diagnose the maturity of the lungs of the fetus.

Cordocentesis is the puncture of the vessels of the umbilical cord of the fetus in order to obtain its blood. This method is performed transabdominally under ultrasound guidance. Manipulation is carried out in the second and third trimesters of pregnancy. This invasive method is used both for the diagnostic purpose of various diseases of the fetus, and for therapeutic purposes.

Chorionic biopsy (chorionbiopsy) - obtaining chorionic villi and their further detailed study. The implementation of this invasive method is diverse. Currently, aspiration transcervical or transabdominal puncture chorionbiopsy is most often used in the first trimester of pregnancy. The sampling (aspiration) of the material (chorion) for research is carried out under the control of ultrasound scanning using a special catheter or a puncture needle inserted into the thickness of the chorion. The main indication for this diagnostic method is the prenatal diagnosis of congenital and hereditary diseases of the fetus.

Aspiration of fetal urine is advisable in obstructive conditions of the urinary system. It is performed by puncture of the bladder or renal pelvis of the fetus under ultrasound guidance. The urine obtained in this case is subjected to an extended biochemical study to assess the functional state of the renal parenchyma and clarify the question of the need for antenatal surgical correction.

Fetal skin biopsy is an invasive diagnostic method based on obtaining fetal skin by aspiration or forceps under ultrasound control or fetoscopic control for the purpose of prenatal diagnosis of hyperkeratosis, ichthyosis, albinism and other diseases (mainly skin and connective tissue).

A tissue biopsy of tumor-like formations is performed by aspiration sampling of tissues of a solid structure or the contents of cystic formations in order to diagnose and select tactics for managing this pregnancy.

Liver tissue biopsy - obtaining samples of fetal liver tissue by the same aspiration method for the diagnosis of diseases during pregnancy associated with a deficiency of specific liver enzymes.

Amnioscopy as a method of diagnosing pregnancy

Amnioscopy is a method that allows you to examine the fetal membranes and amniotic fluid, which are visible through intact membranes (amnion and smooth chorion) adjacent to the internal os. Carrying out amnioscopy at a later date is possible due to the fact that you can enter the amnioscope without any difficulty.

The amnioscope is a special device equipped with a lighting fixture that allows you to visually evaluate the condition of the fetal membranes and amniotic fluid.

In the normal course of pregnancy, the nature of the waters is as follows: transparent or slightly cloudy (due to the admixture of cheese-like lubricant, epidermis and vellus hair). If green waters are determined, we can talk about the presence of hypoxia or fetal asphyxia. This situation is possible with a number of pathologies (the presence of preeclampsia of the second half, an infectious disease with a rise in temperature during pregnancy, etc.). Amnioscopy also allows you to clarify the presence of polyhydramnios, premature rupture of amniotic fluid and identify changes that occur during intrauterine death of the fetus.

Non-invasive diagnostic method in pregnant women - amniocentesis

The next method of diagnosing pregnancy is amniocentesis. This method is performed by puncturing the membranes and extracting a small amount of water for research. This method is performed strictly according to the indications (suspicion of severe hemolytic fetal jaundice, severe asphyxia, etc.).

In the future, a biochemical study of the obtained waters allows you to accurately establish the diagnosis. It should be noted that it is possible to examine the obtained waters for genetic composition, which makes it possible to determine the sex of the fetus (by the content of sex chromatin), the presence of chromosomal aberrations (anomalies).

Non-invasive diagnostic methods during pregnancy

After examining the external genital organs and the mucous membrane of the entrance to the vagina, pregnancy is examined using mirrors. It is with the help of this non-invasive diagnostic method during pregnancy that it is possible to detect the presence of cyanosis of the cervix and vaginal mucosa (a likely sign of pregnancy), as well as to detect diseases of the cervix and vagina, such as

• inflammatory process,
• cervical erosion,
• polyp,
• cancer, etc.

Used in the study of pregnancy with the help of mirrors, folding and spoon-shaped mirrors. The folded speculum must be inserted up to the vault of the vagina in a closed form, and then the folds are opened, and the cervix becomes available for inspection. The walls of the vagina are examined with the gradual removal of the mirrors from the vagina at the end of the study.

Sufficiently good access for examining the cervix of the vagina is created using spoon-shaped mirrors. First, the posterior mirror is inserted, placed on the back wall of the vagina and slightly pressed on the perineum. Further, parallel to it, an anterior mirror (flat lifter) is inserted, with which the anterior wall of the vagina is raised. After examining the cervix and vaginal vaults, the mirrors are removed and manual vaginal examination is started.

Bimanual research method during pregnancy

Having finished feeling the cervix, proceed to a two-handed study. The fingers inserted into the vagina are placed in its anterior fornix, the cervix is ​​slightly pushed back. With the fingers of the left hand, gently press on the abdominal wall towards the cavity of the small pelvis, towards the fingers of the right hand, located in the anterior fornix. Bringing together the fingers of both investigating hands, find the body of the uterus and determine its position, shape, size, consistency. Next, a study of the fallopian tubes and ovaries is performed. To do this, the fingers of the inner and outer hands are gradually moved from the corners of the uterus to the side walls of the pelvis. The diagnosis of pregnancy is completed with the help of mirrors by probing the inner surface of the pelvic bones:

• inner surface of the sacrum,
• side walls of the pelvis
• and symphysis, if available.

They find out the approximate capacity and shape of the pelvis, try to reach the cape, measure the diagonal conjugate.

Bimanual vaginal examination of pregnancy using mirrors determines the following signs.

An increase in the size of the uterus, which becomes noticeable already at the 5-6th week of pregnancy. An increase in the uterus is initially noted in the anteroposterior size (becomes spherical), while later its transverse size also increases. The longer the gestation period, the clearer the increase in uterine volume. By the end of the second month of pregnancy, the uterus increases to the size of a goose egg, at the end of the third month of pregnancy, the bottom of the uterus is at the level of the symphysis or slightly above it.

The sign of Horvitz-Hegar is characterized by the fact that the consistency of the pregnant uterus is soft, and the softening is especially pronounced in the isthmus. As a result, with the two-handed vaginal diagnostic method, the fingers of both hands meet in the isthmus almost without resistance. This symptom is most characteristic of early pregnancy.

Piskacek's sign is characterized by the appearance of uterine asymmetry in early pregnancy. This is manifested by the appearance of a dome-shaped protrusion of the right and left corners of the uterus. The place of protrusion corresponds to the place of implantation of the fetal egg. In the future, as the fetal egg grows, the protrusion disappears.

The sign of Snegireva is characterized by a change in the consistency of the uterus during pregnancy. The softened pregnant uterus during a two-handed examination under the influence of mechanical irritation becomes denser and shrinks in size. After the cessation of irritation, the uterus again acquires a soft texture.

Genter's sign is characterized by the occurrence of an anterior inflection of the uterus in the early stages of pregnancy as a result of a strong softening of the isthmus, as well as the appearance of a ridge-like thickening (protrusion) on the anterior surface of the uterus along the midline. The appearance of thickening, however, cannot always be determined.

The Gubarev-Gauss sign is characterized by the appearance of slight mobility of the cervix. In early pregnancy, slight displacement of the cervix is ​​associated with significant softening of the isthmus.

The presence of the above signs in combination with probable signs makes it possible to assume or accurately diagnose pregnancy. If there is any doubt about the identification of signs, the woman should be asked to return for a follow-up examination in 1–2 weeks. During this time, the uterus increases in size, and all signs become apparent.

Rectal examination in diagnostics in pregnant women

In pregnant women in the second half of pregnancy, rectal examination should also not be neglected.

The study is carried out with gloves. Lubricated with vaseline, the second finger is inserted into the rectum and the neck, presenting part, identification points, pelvic walls are felt.

Outside of the contraction, a slow downward pressure is made towards the descending head. As a result, the location of the head can be determined. So, if the head is located in the outlet or in the narrow part of the pelvic cavity, it is determined quite easily, and if it is in the wide part, it is difficult.

Genter's method gives an idea of

• degree of smoothing of the neck and opening of the pharynx,
• the condition of the fetal bladder (if it is intact and tense), the presenting part and identification points,
• as well as the relation of the head (or buttocks) to one or another plane of the pelvis.

Biological methods for diagnosing pregnancy

Also in this situation, resort to biological methods for diagnosing pregnancy. This non-invasive diagnosis is also essential in recognizing some types of pathological pregnancies. For example, it is not always easy to distinguish an ectopic pregnancy from inflammation of the uterine appendages, it is often difficult to differentiate pregnancy from a uterine tumor, etc.

The first moment of the biological method for diagnosing pregnancy is to establish the presence of human chorionic gonadotropin in the urine. This can be done using the Ashheim-Zondex or Friedman reaction, the implementation of which involves the injection of the urine of a pregnant woman subcutaneously into immature mice, which leads to the growth of the uterus and ovarian follicles in these animals, as well as the appearance of hemorrhages in the cavity of enlarged follicles. However, these methods are practically not used in modern obstetrics. The Friedman reaction also implies the introduction of pregnant urine only to rabbits.

Also, the presence of chorionic gonadotropin in the urine of a woman is practically not used at the present time to diagnose pregnancy, a hormonal reaction in frogs. This reaction consists in the fact that the test urine, introduced into the dorsal lymphatic duct of a male frog, in the presence of a hormone in it, causes the release of spermatozoa after 1–2 hours.

You can also establish the presence of this hormone in the urine using special test systems that are easy to purchase at a pharmacy (pregnancy test). In this case, the woman herself performs the determination of the presence of the hormone in the urine.

Immunological non-invasive method for diagnosing pregnancy

To diagnose pregnancy, it is possible to use an immunological method based on the reaction between chorionic gonadotropin in the urine of pregnant women and antiserum. The most commonly used diagnostic method is based on inhibition of the hemagglutination reaction of erythrocytes treated with chorionic gonadotropin with an appropriate antiserum in the presence of chorionic gonadotropin contained in the urine of pregnant women.

Antiserum is obtained after immunization of rabbits. If the test urine contains chorionic gonadotropin, and, therefore, the woman whose urine is examined is pregnant, then the hemagglutination reaction will not occur (chorionic gonadotropin will bind antibodies).

Also, a modern method for diagnosing pregnancy for the presence of chorionic gonadotropin in the blood serum is the radioimmunological method, which makes it possible to determine the level of chorionic gonadotropin equal to 0.12–0.50 IU / ml in 5-7 days. There are even more modern radioimmunological methods that determine the beta chains in the chorionic gonadotropin molecule already at its level of 0.003 IU / ml. The implementation of these methods requires only 1.5–2.5 minutes.

Instrumental research methods in the second half of pregnancy

In the second half of pregnancy, instrumental research methods are also used.

The necessary research methods in the second half of pregnancy are phonocardiography and electrocardiography - methods aimed at listening and recording fetal heartbeats.

Phonocardiography allows you to identify low frequencies of oscillations emanating from the fetal heart, which are not captured by auscultation. This method accurately reflects the mode of fetal cardiac activity - acceleration, slowdown, arrhythmia, etc., which, in particular, is a diagnostic criterion for fetal hypoxia and asphyxia.

Electrocardiography allows you to fix the cardiac activity of the fetus from 14-16 weeks of pregnancy, which is impossible with phonocardiography.

It also provides important information ultrasound procedure. The ultrasound method allows you to determine

• fruit size,
• presenting part,
• cord length,
• her twist,
• location of the placenta
• nature of amniotic fluid, etc.

Invasive procedure

Invasive procedure(from the New Latin invasivus; from invado - “I go inside”) - a medical procedure associated with penetration through the natural external barriers of the body (skin, mucous membranes).

An example of the simplest invasive procedure is any injection, the most complex is surgery. This is the main way in which the surgeon, unlike the therapist, provides care to the patient.

Invasive procedures can also be used for diagnosis. Examples of invasive studies are invasive cardiac electrophysiological examination) and invasive genetic testing of the embryo.

see also

Notes

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Currently, medicine has stepped far ahead and allows you to assess the state of health of a child even at the stage of its intrauterine development. Such an assessment is of great importance, since the percentage of intrauterine malformations of the fetus and hereditary diseases does not decrease. Prenatal diagnosis of the fetus allows you to timely identify almost all deviations from the norm and take the necessary measures.

Prenatal diagnosis: what is it?

Prenatal diagnostics Prenatal or prenatal diagnostics is a set of studies of the fetus, which allows you to identify or refute intrauterine developmental anomalies, chromosomal and gene diseases of the unborn child. Prenatal diagnostics is the youngest, but successfully developing branch of reproductive medicine. After receiving the results of the study, medical genetic counseling of the spouses is carried out and the questions are resolved: does it make sense to prolong the pregnancy, is it possible to treat a child with an identified pathology after birth or in utero, and how to prevent deviations from the normal development of the fetus in the next pregnancy.

Methods of prenatal diagnosis

All methods of prenatal diagnosis are divided into 2 groups. The first is minimally invasive or non-invasive prenatal diagnostics(prenatal screening), including:

• ultrasound procedure;
• study of the pedigree of parents;
• conducting a genetic study of spouses;
• Doppler ultrasound (assessment of blood flow in the mother-placenta fetus) according to indications;
• cardiotocography (performed from 32 weeks, according to indications from 28 weeks);
• blood for the content of serum markers (“for fetal deformities”).

The second group includes invasive methods which involve surgical penetration into the uterine cavity:

• chorion biopsy;
• placentocentesis;
• cordocentesis;
• amniocentesis;
• biopsy of fetal tissue.

Non-invasive prenatal diagnosis

Prenatal screening (screening or sorting) is mandatory among all pregnant women and includes 2 main studies that can identify gross malformations and markers of fetal pathology.

Ultrasound procedure

Ultrasound is an absolutely safe method and should be performed during pregnancy at least 3 times and at certain times: at 10-14 weeks, at 22-24 weeks and at 32-34 weeks. Deviation from the recommended terms significantly reduces the percentage of detection of pathology. So, at the first ultrasound, certain signs indicating a gross pathology have not yet appeared before the 10th week, and after the 14th week they have already disappeared. But even during the second ultrasound, it is not always possible to identify pathology and malformations (for example, small defects in the septa of the heart). Therefore, ultrasound is necessarily (in any case) supplemented by a blood test for fetal markers.

Ultrasound technique:

• Transabdominal examination
  It is carried out using a transabdominal probe that emits ultrasonic waves. The sensor is guided along the surface of the anterior abdominal wall, and the waves transmitted by it are reflected from the tissues of the unborn baby and processed by a computer. After that, a sonogram is formed on the monitor - an image that is described by the doctor. Transabdominal examination is best performed in the second - third trimesters.
• Transvaginal examination
  It is preferable to carry out in the early stages of gestation. A vaginal probe placed in a condom is inserted into the vagina.

What can be detected by ultrasound:

• localization of the embryo (uterine or ectopic pregnancy);
• the number of fruits;
• gestational age in weeks;
• fetal growth retardation;
• gender of the child;
• localization of the placenta (previa, low placentation);
• the state of the placenta (heart attack, calcifications, degree of maturity);
• the amount of amniotic fluid (poly- or oligohydramnios);
• the condition of the umbilical cord, the number of vessels in it, the knot of the umbilical cord;
• myometrial tone (hypertonicity with the threat of interruption or premature birth);
• fetal heartbeat and its character (bradycardia, tachycardia);
• impaired blood flow in the placental vessels;
• anomalies in the development of the fetus (primarily malformations of the neural tube, heart and kidneys, pathology of the liver and intestines, the condition of the limbs and the facial part of the skull);
• determination of early specific symptoms of Down syndrome (up to 12 weeks) - the width of the cervical-collar space;
• position (longitudinal, transverse, oblique) and presentation (head, pelvic, facial) of the fetus.

In addition, ultrasound can diagnose hydatidiform mole and anembryony (absence of an embryo).

Biochemical screening

For biochemical screening, venous blood of a pregnant woman is examined, taken at 15–20 weeks (optimally at 16–18). The first stage of screening - a "double test" is carried out at 9-13 weeks, during these periods placental proteins PPAP-P and hCG are determined, in Russia it is rarely performed. The second stage of biochemical screening is carried out in the second trimester of pregnancy and the content of alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG) and free estriol is determined. In the Russian Federation, only the first 2 markers are being studied.

What allows to reveal biochemical screening:

• Down syndrome or trisomy;
• anomalies in the development of the brain and spinal cord (absence of the brain - anencephaly, hernia of the brain and spinal cord);
• chromosomal abnormalities.

The advantages of biochemical screening include:

• high efficiency (detection of Down syndrome and neural tube defects reaches 70%);
• early diagnosis of fetal pathology (15-22 weeks), when pregnancy can still be terminated;
• no risk to the fetus.

Among the shortcomings, it is worth noting the influence of various factors (multiple pregnancy, complications of gestation, diseases of the female genital organs, and others) on the reliability of the results. Therefore, the study of biochemical markers may show a false negative or false positive result.

In suspicious cases of deviations from the norm of biochemical markers, an ultrasound of a higher level (in the perinatal center or in the regional / republican hospital) and invasive prenatal diagnostics are prescribed.

Invasive prenatal diagnostics Prenatal invasive diagnostics provides a 100% guarantee of results (detection of hereditary diseases, malformations and chromosomal aberrations), and is also distinguished by the rapid receipt of research results. Also, the advantages of invasive diagnostics include the detection of pathology in short terms of pregnancy (up to 14 weeks), and parents are given a choice: either have an abortion or prolong the pregnancy. If the embryo is preserved, doctors have enough time to correct malformations and treat fetal diseases in utero.

Indications for invasive prenatal diagnosis

Given the introduction into the uterine cavity during invasive methods, they are performed according to strict indications:

• the age of the woman (all mothers over 35, as the risk of fetal chromosomal abnormalities increases with age);
• consanguineous marriage;
• burdened history: miscarriages in the early stages, the birth of a child with a chromosomal abnormality;
• chromosomal pathology in one of the future parents;
• the need to determine paternity;
• deviations from the norm in the blood of serum markers;
• exposure of parents to mutagenic factors (radiation, polluted environment, chemicals, medication, etc.);
• a history of the birth of a child with congenital malformations, mental retardation or hereditary metabolic diseases (phenylketonuria);
• deviations from normal biochemical markers;
• ultrasound signs of fetal anomalies.

Methods of invasive prenatal diagnosis

Chorionic biopsy
The method consists in the collection and subsequent study of chorion cells. The chorion is the germinal membrane, which in the future will be transformed into the placenta. Chorionic biopsy is performed at 10-11 weeks of gestation in two ways:

• Transcervical method
  Suction of a small amount of chorion tissue with a syringe through a cervical catheter (installed in the cervical canal).
• Transabdominal way
  The uterus is punctured through the anterior abdominal wall with a syringe with a long needle and the chorionic tissue is taken.

Chorionic biopsy is carried out under ultrasound control. Usually performed under local anesthesia. The results of the analysis are ready in 3-4 days. The advantages of the method include its speed of obtaining results, which makes it possible to terminate a pregnancy at a safe time, identify gene and chromosomal diseases, confirm paternity and determine the sex of the embryo.

Placentocentesis
The method is similar to a chorion biopsy, placental cells are also taken, but at a later date (second trimester of pregnancy). It is also possible to obtain placental cells when entering the uterus through the cervical canal or by puncturing the anterior abdominal wall. Unlike a chorionic biopsy, culture of cells obtained by placentocentesis may not be indicative, which requires a repeat of the procedure.

Carrying out amniocentesis significantly increases the risk of possible complications of pregnancy due to long terms and is carried out only in a hospital with subsequent (at least 3 days) hospitalization.

Amniocentesis
The method consists in taking amniotic fluid by puncturing the anterior abdominal wall, uterus and amnion. The amniotic fluid is examined for the content of hormones, enzymes and amino acids, on which the growth of the fetus depends. Together with the amniotic fluid, it examines the desquamated epithelial cells of the fetal skin and urinary tract. The study is carried out at 16 - 18 weeks. The method is highly informative and its efficiency reaches 99%. The disadvantages include the duration of the analysis (from 2 weeks to 1.5 months). Allows you to diagnose gene and chromosomal aberrations, determine the maturity of the lungs of the fetus, the severity of the Rh conflict, some anomalies in the development of the fetus and the degree of intrauterine hypoxia.

Cordocentesis
The method consists in taking fetal blood from the umbilical cord. It is carried out at 18 - 24 weeks and allows you to identify not only chromosomal and gene abnormalities, but the immunological and hormonal status of the fetus, determine the biochemical parameters of blood, and so on. The results of the analysis are prepared in 4-5 days. Cordocentesis in terms of diagnostic efficiency approaches 100%.

Fetal tissue biopsy

It is carried out in the second trimester, under mandatory ultrasound control. The study is indicated to determine severe hereditary skin diseases in an unborn child - hyperkeratosis and ichthyosis. With these pathologies, the process of keratinization of the skin is disrupted, which leads to a thickening of the surface layer, and the skin looks like fish scales.

The material is taken in the same way as when receiving chorionic or placental tissue. A special long needle inserted into the uterine cavity is equipped with tweezers, which capture and separate a small piece of skin. After the material is sent to the study, which includes three types:

• Cytogenetic study
  Allows you to determine the number of chromosomes, the presence of additional or lack of chromosomes. For example, with Down's syndrome, an additional 21 chromosome is detected, with Klinefelter's syndrome in a pair of sex chromosomes in a male fetus, extra X or Y chromosomes, with Turner's syndrome, there is a lack of an X chromosome in a girl.
• Molecular genetic study
  This method allows you to identify intrachromosomal defects, that is, gene mutations, as a result of which certain diseases develop: hemophilia, phenylketonuria, Duchenne muscular dystrophy and cystic fibrosis.
• Biochemical research
  Allows you to assess the maturity of the lungs and determine its degree, diagnose fetal hypoxia (metabolic acidosis), identify Rh conflict and its severity.

Disadvantages of invasive diagnostics

Despite all the advantages and high information content of invasive prenatal diagnostic methods, they also have a number of negative points:

• the threat of abortion (antispasmodics are prescribed for prevention before and after the procedure, as well as hospitalization, the duration of which depends on the method used);
• abortion;
• the risk of intrauterine infection of the fetus;
• the risk of increasing the severity of the Rh conflict;
• risk of prenatal rupture of water during amniocentesis;
• the risk of bleeding in a woman;
• risk of placental abruption.

Contraindications to invasive diagnostics

Invasive prenatal diagnosis is not indicated for the following conditions of a woman:

• the threat of termination of pregnancy;
• bleeding from the genital tract;
• placental abruption;
• severe adhesive disease of the small pelvis;
• isthmic-cervical insufficiency;
• anomalies in the development of the uterus;
• pustular lesions of the skin of the abdomen;
• infectious diseases of the mother;
• inflammation of the cervix and vagina;
• large fibroids.

Also, a contraindication is the categorical refusal of a woman to conduct an invasive prenatal diagnosis.

Prenatal diagnosis is a set of methods used to detect pathologies at the stage of intrauterine development. It allows with a high degree of probability to determine the genetic and other disorders of the fetus. In case of confirmation of an anomaly of development, parents decide on further bearing or termination of pregnancy. Thanks to a comprehensive examination, with almost 100% certainty, it is possible to determine the paternity of the child and his gender.

To date, prenatal screening is a new, but dynamically developing and very promising area in medicine. First of all, it is indicated for pregnant women who are at risk.

Diagnosis of diseases

Prenatal diagnosis of chromosomal diseases allows you to establish the following pathologies.

Down syndrome

The most common chromosomal disorder, occurs in one in eight hundred newborns. A person with this pathology has an additional 47 chromosome. In addition to the characteristic appearance, children with Down syndrome are often diagnosed with strabismus, hearing impairment, severe pathologies of the cardiac and gastric systems, and mental retardation.

It is possible to determine the presence of pathology in the fetus by an increase in the collar zone, the absence of a nasal bone, with anomalies in some parts of the intestine and pathological changes in the blood test of a pregnant woman. The final diagnosis is made, taking into account the totality of the results obtained using direct and indirect methods of prenatal diagnosis.

Shereshevsky-Turner syndrome

A genetic disease that occurs when one of the X chromosomes is missing or damaged. Occurs only in females. Symptoms of the disease: growth retardation, short thick neck, abnormally shaped auricles and hearing loss, delayed puberty, underdevelopment of the mammary glands, lack of menstruation (). Intellectual development, as a rule, does not suffer. Adult women with Turner syndrome are infertile.

X-trisomy syndrome

Occurs only in females. The disease develops due to the presence of three X chromosomes in the genotype. Symptoms of the disease are profound mental retardation, underdevelopment of the genital organs, infertility.

Hemophilia

A hereditary disease associated with blood clotting disorders, which affects mainly men. The carriers of the hemophilia gene are women who pass the disease on to their sons. The likelihood of developing hemophilia increases with family ties of parents. There may be bleeding into the joints and internal organs, which occur as a result of even a minor injury. The cause of the pathology is a mutation of one gene on the X chromosome.

Klinefelter syndrome

A pathology of chromosomal origin, in which the male genotype has an additional female chromosome. Patients have a delay in physical and speech development, a disproportionate physique, underdevelopment of the genital organs, an increase in the mammary glands, poor body hair growth. Patients with Klinefelter's syndrome have an increased risk of developing epilepsy, diabetes mellitus, hypertension, and schizophrenia. Some patients have moderate mental retardation, difficulties in establishing contacts with other people, and a tendency to alcoholism.

Prenatal diagnosis of congenital pathologies determines:

1. Disturbances in the development of the skull and brain.
2. Hydrocephalus - an imbalance between the production of cerebrospinal fluid and its absorption, often occurs due to fetal hypoxia, infectious diseases, and maternal smoking during pregnancy.
3. Heart defects. Prenatal screening allows you to accurately determine the anomalies in the development of the heart and blood vessels of the unborn child. Based on the data obtained, a decision is made on the need for surgical intervention in the first days, and sometimes even hours after his birth.
4. Absence of kidneys or severe violations of their development. This pathology is diagnosed at 13-17 weeks of gestation. Among the possible anomalies are the absence of a kidney, the presence of a third organ, doubling of the kidney. Pathology is accompanied by growth retardation and general development of the fetus, oligohydramnios, disorders in the formation of the placenta. Termination of pregnancy is due to medical reasons, and, with the consent of the parents, should be carried out no later than 22 weeks. The risk of preterm birth is also high.
5. Anomalies in the formation of limbs.

Methods of prenatal diagnosis

There are non-invasive and invasive methods of prenatal screening.

Non-invasive prenatal diagnosis

It does not pose the slightest danger to both the woman and her unborn child. When it is carried out, surgical procedures are not performed that could injure the fetus. Such methods are indicated for all pregnant women, regardless of age, health status or the presence of hereditary diseases.

The data (indirect methods) of the examination include ultrasound diagnostics () and the study of the blood serum of a pregnant woman.

Ultrasound procedure

Ultrasound in prenatal diagnosis is included in the category of planned and mandatory procedures in pregnant women. Refusal of this examination does not make sense: the procedure is safe, painless and can determine how successfully the fetus develops, and whether there is a risk of pathologies.

Ultrasound in the first trimester allows you to accurately determine the duration of pregnancy, the number of fetuses, confirm the degree of viability of the embryo, and exclude the presence of hydatidiform mole. produced in 6-7 weeks. If a woman had spontaneous abortions, it is determined how tightly the embryo is fixed in the uterus and whether there is a threat of a second miscarriage.

Ultrasound in the second trimester, performed at 11-13 weeks, can determine the sex of the child, the presence of defects in the heart, kidneys, limbs and other organs, measure the collar zone, determine the presence of fibroids or other neoplasms that interfere with the normal blood supply to the placenta.

Ultrasound diagnostics for a period of 22-26 weeks allows you to see anomalies that have not been previously identified, establish the position of the fetus in the uterus, identify intrauterine growth retardation, diagnose oligohydramnios or.

Screening for serum factors

Produced on the basis of a study of blood samples taken from a vein of a pregnant woman. Usually, the study is carried out in the period from the 16th to the 20th week, in some cases it is allowed to do an analysis for up to the 22nd week.

This screening is also called the "triple test" because it provides information on three substances: alpha-fetoprotein, human chorionic gonadotropin and unconjugated estriol.

Screening with an accuracy of 80% identifies fetal anomalies, in particular Down's syndrome and neural tube closure.

At a period of 11-13 weeks, some other developmental pathologies are detected, such as Patau and Edwards syndromes. The second of these diseases in its frequency is second only to Down's syndrome.

Edwards syndrome is diagnosed with a very high mortality in the first year of life (90% of cases). These children rarely survive to adulthood. Congenital malformations characteristic of this pathology include: low body weight (about 2 kg in a full-term baby), cardiovascular insufficiency, intestinal obstruction, and profound mental retardation.

Diagnosis of Edwards syndrome in early pregnancy is unrealistic, but an ultrasound performed at week 12 can already detect the presence of a hernia of the abdominal cavity and choroid plexus cysts. The prognosis for the survival of such patients is poor.

Invasive (direct methods)

Invasive methods of prenatal screening - obtaining samples of cells and tissues of the embryo, placenta and fetal membranes in order to study them.

These are methods such as:

• chorionic villus biopsy;
• biopsy of fetal tissue;
• fetoscopy.

Let us consider in more detail when and how these procedures are carried out.

Amniocentesis

Collection of amniotic fluid to study their chemical composition. This analysis allows you to establish the degree of maturity of the fetus, to identify a lack of oxygen supply (), to determine the Rhesus conflict of the fetus and mother. The procedure is indicated for 15-16 weeks.

Collection of amniotic fluid during amniocentesis

This prenatal diagnosis establishes more than 60 types of hereditary diseases that can be transmitted to a child from parents. The risk of miscarriage during the procedure is small and is no more than 1%.

Chorionic biopsy

The optimal time for this study is the period in the first trimester, up to 12 weeks. The procedure is as follows: using a catheter inserted into the cervix, samples of chorion tissue materials are taken. The manipulation is carried out under local anesthesia, so it is painless, or brings minor discomfort.

After processing and being in the incubator, the chromosomes are analyzed for the presence of genetic abnormalities. Many women are afraid of a biopsy, believing that the procedure can lead to fetal injury and miscarriage. Such a risk does exist, but it does not exceed 1%.

In some cases, after the biopsy, there may be slight pain in the abdomen and leg and minor bleeding. These phenomena do not indicate a deviation from the norm and do not adversely affect the development of the fetus.

Prenatal diagnostic method - chorion biopsy

Chorionic biopsy reveals many disorders, including cystic fibrosis. This is a serious disease in which the production of a specific fat-carrying protein is disrupted. The presence of pathology leads to a violation of the digestive process, a decrease in immunity, and frequent pneumonia. The disease is incurable, but timely diagnosis makes it possible to provide conditions that allow patients with this pathology to live to adulthood.

Fetal tissue biopsy

The diagnostic procedure is carried out in the second trimester of pregnancy and is controlled by ultrasound. Its essence lies in the sampling of fetal skin in order to exclude severe skin diseases that are inherited.

This method of prenatal diagnosis establishes the risk of fetal malformations such as ichthyosis, albinism, hyperkeratosis.

Ichthyosis is a rare genetic disease in which there is a deformation of the skin, acquiring a look similar to fish scales. Symptoms of the disease: keratinization, peeling and increased dryness of the skin, the presence of small scales and rashes on it, deformation of the nail plates. There are several varieties of this pathology.

In the presence of ichthyosis that develops in utero, there are frequent cases of miscarriage or the birth of a dead child. If the child survives, his life expectancy is no more than a week. If a disease is detected at the stage of intrauterine development, parents are advised to terminate the pregnancy due to the non-viability of the fetus.

Cordocentesis

This is a method that analyzes a blood sample obtained from the umbilical cord of the fetus. The duration of the procedure is the period after the 20th week, the best time is 22-25 weeks.

Taking blood from the umbilical cord of the fetus (cordocentesis)

Manipulation is performed according to strict indications, when other invasive methods are impossible to use due to the long period:

• mother's age over 35;
• negative results of a biochemical blood test;
• high probability ;
• the presence of a hereditary disease in one of the parents.

Cordocentesis is not performed if a woman is diagnosed with a threatened abortion, in the presence of fibroids, bleeding, during an exacerbation of infectious and chronic diseases.

The study of cord blood allows you to identify such anomalies as Down syndrome, Edwards, Klinefelter. In addition to genetic diseases, it is possible to diagnose Ducheshen's dystrophy, cystic fibrosis, hemolytic disease of the fetus caused by the Rhesus conflict. To date, with the help of this study, you can determine the presence of more than 6,000 diseases.

Fetoscopy

Examination of the fetus with an inserted probe. A visual examination of the child's condition is carried out at 18-19 weeks of gestation. Fetoscopy is applicable solely for medical reasons, since with the introduction of an endoscope, the risk of miscarriage is 7-8%.

Among other invasive methods, placentobiopsy (taking samples of the placenta for analysis) and a study of fetal urine (to determine the severity of kidney pathology) should be highlighted.

Indications for prenatal diagnosis

In what cases is it recommended to undergo an examination to identify possible pathologies of the fetus and how safe is it? Methods of prenatal diagnosis are not recommended for all expectant mothers. Since the use of invasive methods is associated with a certain degree of risk for the child, they are prescribed only for strict medical reasons.

These include:

• mature age of parents (mother over 35 years old, father over 45 years old);
• suspicion of malformations or developmental disorders detected by ultrasound;
• the presence in the family of an older child with chromosomal abnormalities;
• transferred infectious diseases in early pregnancy (,);
• women carriers of hereditary diseases (hemophilia);
• when identifying deviations from the norm of biochemical markers;
• the fact of exposure of one of the parents shortly before the onset of pregnancy.

Not all of these factors necessarily lead to impaired fetal development. So, if the family has an older child with Down syndrome, the probability of having a second baby with the same diagnosis is low. But most parents prefer to play it safe and make sure that the child has no malformations.

As a rule, age parents are offered to undergo an examination, although children with Down syndrome are often born to younger women.

Principles of prenatal diagnosis

The results of prenatal screening are characterized by a high level of reliability and validity. They can both refute fears of the presence of pathology and prepare parents for the birth of a sick child.

Diagnostic procedures should be carried out taking into account the main ethical principles:

1. Availability. All women who have medical indications for this must undergo research. Lack of finance should not be an obstacle to the procedure.
2. Voluntariness. Doctors are obliged to explain to the pregnant woman and her husband the need for the study and the risk of having a sick child. However, all appointments are advisory in nature, the final decision on the need to pass them is made by the spouses.
3. Providing the family with complete information about the condition of the fetus. Parents should have a complete understanding of the nature of the disease of their unborn child, the features of its development, methods of treatment and further prognosis.
4. Prenatal diagnostic procedures are carried out primarily for women who have medical indications for this. Many impressionable women with increased levels of anxiety, who are not at risk, can also undergo these studies, but with full information about their possible consequences.
5. The decision to terminate a pregnancy is made exclusively by the woman and her family members. Any pressure or intimidation from doctors is unacceptable!
6. If the family decides not to terminate the pregnancy, the doctor should familiarize the parents with the specifics of caring for the unborn child and mentally prepare the spouses for their future life with the baby.

The decision on the need for diagnostic procedures is made jointly by an obstetrician-gynecologist, geneticist, neonatologist, pediatric surgeon, taking into account the wishes of the parents themselves.

After reading an article about invasive diagnostic methods during pregnancy, You will learn:

• 1

  Invasive diagnostic methods, indications and contraindications

• 2

  Methods of invasive diagnostics

• 3

  Chorionic biopsy

• 4

  Placentocentesis

• 5

  Amniocentesis

• 6

  Cordocentesis

• 7

  Fetoscopy.

Invasive diagnostic methods are a group of studies that allow obtaining biological material of fetal origin for analysis (amniotic fluid, chorionic or placental villi, skin areas and fetal blood). The purpose of such a diagnosis is to identify fetal malformations, diagnose chromosomal (anomalies in the number and structure of chromosomes) and monogenic (changes in the structure of the gene) diseases.

The choice of method is carried out jointly by a geneticist and an obstetrician-gynecologist, taking into account the gestational age and specific pathology. These methods are dangerous in terms of possible complications, so they are prescribed only if there are appropriate indications.

Indications

1. The age of a woman is over 35 years old (Down syndrome is detected in about one case out of 700 births in the general population, in women over 35 years old - in about one case out of 50-150 births, the same situation is typical for a number of other chromosomal diseases).
2. Previous child(ren) with a history of Down syndrome or other chromosomal diseases or multiple congenital malformations.
3. Ultrasound markers of fetal chromosomal diseases.
4. High risk of having a child with a chromosomal pathology based on the results of biochemical screening.
5. The presence of a chromosomal rearrangement, a hereditary disease or a malformation in one of the spouses.
6. Consanguineous marriage.
7. A history of spontaneous miscarriages, stillbirths, primary amenorrhea, primary infertility in spouses.
8. Adverse effects of environmental factors in early pregnancy (radioactive exposure, inhalation of vaporous poisons, etc.).
9. Taking embryotoxic drugs in early pregnancy.
10. X-ray examination in early pregnancy.
11. Group or Rh incompatibility of mother and fetus.

Contraindications

Contraindications to conducting invasive studies are relative, that is, even if there are contraindications, it may be possible and necessary to conduct a study. For example, one of the main contraindications is the threat of abortion, but the cause of the threat may be fetal malformations, and the study is necessary to determine the further tactics of pregnancy, but the study is carried out against the background of appropriate therapy.

Also contraindications are uterine malformations, high fever, active infectious diseases, fibroid nodes and the location of the placenta in the path of needle insertion.

Methods of invasive diagnostics are prescribed only if the risk of severe disease in the fetus exceeds the risk of complications from such diagnostics. In any case, the decision to conduct the study is made by the family on the basis of the information provided by the doctor, the pregnant woman has the right to refuse to conduct the prescribed study.

Methods of invasive diagnostics

Invasive diagnostics is possible in any of the trimesters of pregnancy. In the first trimester, as a rule, a chorionic villus biopsy (chorion biopsy) is performed, as a rule, this research method is performed at 8-12 weeks of gestation. It is also possible to perform amniocentesis in the first trimester, but since the risk of abortion is high, this study is more often performed in the second trimester.

In the second trimester of pregnancy,:

1. Amniocentesis- this is an operation with which amniotic fluid is obtained for examination, as a rule, it is carried out at a period of 17 - 22 weeks of pregnancy, but sometimes the study is carried out up to 34 weeks.
2. Amnioscopy- this is a method of visual inspection of the lower pole of the fetal egg using a thin endoscope, it is possible to conduct this study from 17 weeks of pregnancy until delivery.
3. Cordocentesis- this is a taking for the study of the blood of the fetus from the umbilical cord for the diagnosis of hereditary blood diseases, intrauterine infection, as well as the treatment of hemolytic disease of the fetus, is carried out from 18 weeks of pregnancy.
4. Placentocentesis- this is a procedure for taking placental cells for analysis for the diagnosis of chromosomal diseases, this study is carried out at a period of 14 - 22 weeks of pregnancy.
5. Fetoscopy- this is an examination of the fetus in the uterus to detect congenital malformations, as well as the study of hereditary and congenital malformations by examining the blood of the fetus, skin and amniotic fluid, as a rule, is carried out at a period of 18 - 24 weeks of pregnancy.

In the third trimester of pregnancy, as a rule, invasive diagnostic methods are not used due to the high risk of preterm birth, but sometimes, if there are strict indications, it is possible to perform amnioscopy, amniocentesis and cordocentesis before delivery.

Depending on the location of the placenta, the following types of access are distinguished: transabdominal (introduction of an instrument through the anterior abdominal wall), transcervical (into the uterine cavity through the cervical canal), transvaginal (pierce the anterior or posterior fornix of the vagina). Chorionic biopsy

Chorion- this is the organ of the fetus, from which the placenta is then formed, its cells are identical to the cells of the fetus.

Chorionic biopsy- this is the taking of several villi from the fetal chorion under ultrasound control, followed by counting the number of chromosomes in its cells. If the number and structure of chromosomes in the chorion cells are normal, then chromosomal diseases in the fetus are excluded with a probability of more than 99%.

The advantages of this method is the duration - up to 12 weeks, if necessary, termination of pregnancy is carried out in the early stages of pregnancy, which is the safest for the woman's body. When performing a chorionbiopsy, about 100 hereditary diseases and pathologies can be detected, including cystic fibrosis, hemophilia, Down syndrome, Edwards, Turner, Klinefelter, etc.

An injection is made with a thin needle through the anterior abdominal wall, the needle passes into the chorion and several chorion villi enter it. The procedure is performed on an outpatient basis, disposable gloves and sterile needles are used, so the risk of infection during the procedure is very small, no more than 0.3%.

When performing a chorionbiopsy, there is a risk of abortion, but if all the rules of the procedure are followed, this risk does not exceed 1%. There is also a risk of an unfavorable course of pregnancy with a Rh conflict (it is possible to stimulate the production of antibodies), the risk of bleeding.

When performing a chorion biopsy, there is a risk of false-positive or false-negative results, which is explained by the phenomenon of "placental mosaicism" - the non-identity of the genome of the embryonic and chorion cells.

Chorionic biopsy can be performed up to 14 weeks of pregnancy, after this period, a placenta is formed at the place of the chorion, and then placentocentesis (biopsy of the placenta) is already performed.

Placentocentesis

Placentocentesis is a procedure in which placental cells are obtained to study their chromosomal and genetic structure. Placentocentesis is similar to a chorionic biopsy, as the placenta is what the chorion develops into over time, but is performed at a later date (14-20 weeks of gestation).

Under the control of the ultrasound machine, a puncture is made with a long needle in the abdomen of the pregnant woman, this special needle is inserted into the placenta, as a result, a column of placental cells remains in it, which will be further examined.

The main goal of placentocentesis is to obtain fetal material for the detection of chromosomal and gene diseases in the fetus. If a pathology is detected, it is possible to terminate the pregnancy for medical reasons.

Complications with placentobiopsy are similar to those with chorionbiopsy. Placentobiopsy leads to premature termination of pregnancy in 1-3% of cases, this occurs due to reflex contraction of the walls of the uterus.

Amniocentesis

Amniocentesis- this is a puncture of the amniotic sac with the collection of a small amount of amniotic fluid. This method makes it possible to determine a larger number of indicators. In addition to gene and chromosomal diseases, it is possible to determine biochemical parameters that can be used to judge possible metabolic disorders, the presence of certain diseases. For example, with the help of amniocentesis, the degree of maturity of the lungs of the fetus, the presence of hypoxia, and Rh conflict are determined.

Under ultrasound control, a syringe is inserted into the uterine cavity through the anterior abdominal wall, into which a material of 20-30 ml is collected. In addition to the amniotic fluid itself, a small amount of fetal cells (thickened epithelium) also enter the syringe, which are also examined. The result of the analysis, as a rule, is ready in 2-3 weeks.

Possible complications of amniocentesis: termination of pregnancy, leakage of amniotic fluid, infectious complications, bloody discharge from the genital tract, worsening of the course of the Rh conflict, but the likelihood of complications in this study is less than when performing a chorionic biopsy.

Cordocentesis

Cordocentesis is a puncture of the vessels of the umbilical cord. The material is taken by puncturing the anterior abdominal wall under ultrasound control and obtaining cord blood. The study can be carried out after the 18th week of pregnancy. Cordocentesis allows you to perform almost all the tests that can be done from a regular blood test (hormonal examination, biochemical parameters, infections, immunological conditions, etc.), and, like all other methods of invasive diagnostics, it helps to identify gene and chromosomal diseases. But this method is used not only as a diagnostic procedure, but also as a therapeutic one (administration of drugs, intrauterine blood transfusion to the fetus, for example, in severe Rh conflict). Amniocentesis and cordocentesis can be used to diagnose infections.

Termination of pregnancy can also become a complication of cordocentesis. As a rule, the analysis is performed 4-5 days.

Fetoscopy

Fetoscopy is a method of examination of the fetus, which allows you to directly examine the fetus through a thin endoscope and obtain blood or pieces of skin for analysis. This method is used as the last stage of a genetic examination for suspected congenital malformations and hereditary skin diseases. As a rule, the study is carried out at 18 - 24 weeks of pregnancy, after the use of other invasive methods for diagnosing hereditary diseases of the fetus.

Fetoscopy is carried out under mandatory ultrasound control and only in a hospital. An incision is made on the skin of the anterior surface of the abdomen and the wall of the uterus and a special device is inserted into the uterine cavity - a fetoscope, which allows you to examine the fetus for the presence of gross malformations, and with the help of special forceps you can take a piece of the skin of the fetus for examination, if necessary, blood is taken from a thin hollow needle from the umbilical artery, as in cordocentesis.

Possible complications: abortion (in 5-10% of cases, so this method is used very rarely), bleeding, hematomas on the skin of the fetus, infection of the fetus.

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