Invasive prenatal diagnosis of the fetus

Prenatal studies are conducted due to the high incidence of chromosomal abnormalities in fetal development, which rank 2nd in the structure of fetal death and infant mortality. Invasive prenatal diagnostics are necessary if non-invasive methods are positive and the woman is at risk.

Invasive intervention is more time-consuming and can cause serious postoperative consequences. However, since its informational content is higher, BMI is indispensable in assessing the risk of hereditary diseases and fetal chromosomal abnormalities.

During the initial visit to theIVMEDMedical Center, a combined ultrasound and biochemical screening is performed with a computerized calculation of the risk of chromosomal abnormalities in the fetus. If there is a high risk of fetal genetic abnormalities, the patient is recommended to undergo an invasive test.

The use of non-invasive screening tests allows for the appointment of IMD in the first trimester of gestation, which reduces the risk of postoperative complications and is less traumatic for the mother and fetus.

Indications and contraindications for diagnostics
The risk group requiring mandatory invasive testing includes female patients:

• at the age of > 35 years, as the risk of chromosomal mutations increases with age, even in the absence of gynecological pathologies;
• with detected fetal abnormalities on ultrasound;
• with increased activity of proteins in the blood serum;
• married to a close relative;
• with congenital malformations, chromosomal aberrations (abnormalities) or hereditary diseases. The same goes for a sexual partner;
• whose previously born child had developmental defects or inherited pathologies;
• with miscarriages, stillbirths, and primary infertility;
• living or working in unfavorable and dangerous conditions;
• embryotoxic drugs taken in early gestation or infectious diseases;
• underwent radiation exposure in the first trimester of pregnancy;
• whose sexual partner was subjected to chemotherapy or radiotherapy before conception;
• with a negative Rh factor or blood group incompatibility with the fetus.

Contraindications to the IPA are:

• inflammatory processes of the skin in the area of the puncture or internal and external genital organs;
• risk of spontaneous abortion;
• blood clotting disorders;
• the presence of myomatous nodes of significant size;
• histico-cervical insufficiency;
• congenital anomalies of the uterus;
• the presence of an active adhesive process in the pelvis.

The risk of miscarriage as a result of IUI is only 2-4%. The longer the gestation period, the lower the risk of miscarriage. At the Rodinnyi Dzherelo Medical Center, this risk is minimal, as it depends on the doctor’s professionalism, the clinic’s technical equipment, the chosen examination method, and the patient’s condition.

IPA is performed only with the patient’s consent. Often, patients miss the opportunity for early diagnosis of fetal anomalies due to lack of awareness and exaggeration of the possibility of developing postoperative complications.

Specialists of theIVMEDMedical Center consult the patient, explain the need for the study and the existing risks. This allows a woman to make an informed decision and increases the possibility of a favorable pregnancy outcome for both the fetus and the mother.

Methods of invasive research

Prenatal invasive methods of examination differ depending on the gestational age. In the first trimester, a biopsy of the chorionic villi, the fleecy membrane around the implanted egg, is performed. The test is performed at 11-12 weeks of gestation and allows detecting fetal chromosome abnormalities and gene abnormalities at an early stage.

There are two ways to collect material for research:

• intravaginal access. A thin catheter is inserted through the vagina into the uterine cavity, and the villi tissue is sampled;
• abdominal approach. A puncture is made in the abdominal and uterine wall and the material is taken with a syringe. The biopsy is taken under the control of an ultrasound machine. The disadvantage of the method is the possibility of obtaining an erroneous result due to the non-identity of the chromosomal material of the embryo and chorionic cells.

Amniocentesis is also performed – sampling of amniotic fluid for analysis. The diagnostic procedure is performed both in the first trimester (17-22 weeks) and in the second trimester at 34 weeks. The technique allows determining the degree of maturity and sex of the fetus, heart pathologies and hemolytic diseases, and abnormalities in the development of the fetal nervous system.

The disadvantage of the method is the long (2-3 weeks) waiting time for the results, since it takes time to increase the number (multiplication in a special medium) of the fetal cells obtained.

In the second trimester of gestation, in addition to amniocentesis, it is prescribed:

Amnioscopy is a visual examination of the lower part of the ovum using an endoscopic system of the smallest diameter. The test is performed starting from the 17th week of pregnancy and according to indications for childbirth.
Placentocentesis is a method of taking placental cells for research. This method is much like a chorionic villus biopsy and is performed at 16-20 weeks of pregnancy. The disadvantage of the method is that, if necessary, the termination of pregnancy is carried out at a later stage, which is more traumatic for the woman.

Cordocentesis is a blood sampling from the umbilical cord vein. The test helps to detect blood diseases in the fetus, the presence of an infectious agent, or determine a Rh conflict. The test is scheduled from the 18th week of gestation. The method allows performing a wide range of blood tests, as well as therapeutic procedures (fetal blood transfusion, administration of medications) in utero. Relative contraindications to the examination are low- or high-fetal weight, and poor fetal position.
Fetoscopy is a visual examination of the fetus, which is performed using the optical system of the endoscope, which allows to detect anatomical malformations. With the help of microsurgical instruments inserted through the surgical channel of the endoscope, a sample of the fetal skin or muscle can be taken. The method is used at 18-24 weeks of pregnancy.
The material obtained as a result of the IMD is sent for research.

Methods of biopsy examination

The obtained material is subjected to the following research methods:

• cytogenetic, which can detect abnormalities in the number of chromosome pairs;
• molecular genetic – the method makes it possible to study the structure of a chromosome and determine the presence of defects in its structure;
• biochemical – this set of research methods allows us to assess the maturity of the fetal organs and the degree of risk of Rh conflict.
• The results obtained make it possible to predict the further course of pregnancy and justify the choice of outcome. The Rodinne Dzherelo MC uses automatic and semi-automatic methods of material processing for research, which allows to reduce the time for obtaining results and reduce the influence of the human factor.

Risks of postoperative complications

Even the safest invasive research methods can lead to negative consequences in the form of:

• premature discharge of amniotic fluid;
• premature birth;
• trauma and intrauterine growth retardation of the fetus;
• detachment of the child’s seat;
• violation of the integrity of the umbilical cord;
• injuries of organs located in close proximity to the uterus;
• introduction of infection inside the fetal bladder.

AtIVMED, these risks are minimal, as the intervention is carried out:

• under the control of high-quality ultrasound equipment;
• by high-class specialists with extensive practical experience;
• after a thorough examination of the anamnesis;
• taking into account the patient’s individual characteristics and condition.
• The risks of pregnancy termination during IMD are comparable to the general population risks.

The most dangerous procedure is cordocentesis. During this procedure, the risk of miscarriage is 3.3%. However, thanks to the high professionalism of the Rodinne Dzherelo Medical Center staff, these figures can be reduced to a minimum, as timely treatment and non-invasive screening tests allow for less traumatic methods in the early stages of pregnancy.