Genetic analysis during pregnancy

, medical expert
Last reviewed: 19.10.2021

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Genetic analysis during pregnancy needs to pass necessarily, this is the most correct option to calculate the probability of development of pathologies and hereditary defects in a future child.

Also, the test should be done if:

  1. It takes a long time for conception or pregnancy to end with miscarriage. The cause may be in the defects of the chromosomes of the father and mother.
  2. If the age of parents is 35 years. In this case, the probability of mutations and chromosomal abnormalities is significantly increased.
  3. Also, for the passage of a genetic analysis, a pregnant woman can be guided by a doctor, relying on the history data:
    • The future mother or father has serious illnesses that are inherited.
    • The family already has children with deviations in the set of chromosomes.
    • The future mother is more than 30-35 years old.
    • If the future mother in the first half of pregnancy took serious medications, drugs, alcoholic beverages.
  4. Another indication for a genetic test may be the suspicion of a frozen pregnancy during an ultrasound examination.
  5. When changes in biochemical tests also need to pass a genetic analysis.

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Down Analysis in Pregnancy

Analysis for Down in pregnancy should be taken necessarily, but it is still better to do this analysis before planning a child to calculate the probability of a baby with deviations from a specific pair. The likelihood that a young couple will have a child with Down's syndrome is also not excluded.

The most accurate result is provided by the combined diagnostic method, consisting of ultrasound diagnostics, where the thickness of the collar zone is assessed and the detection of special markers in the blood serum. It is best to diagnose Down's syndrome and other chromosomal abnormalities at the 16-18 week of bearing a child. This term makes the so-called "triple test", and only in one percent of cases it gives a false result. But it is better to take several tests - so you can get the most accurate result. So, with a positive test for Down's syndrome, an amniotic fluid is additionally performed (but only if the future mother does not have contraindications to an amniocentesis ).

Do not despair if the result of the test is positive - the probability of a diagnostic error is not ruled out. In this case, it is better to repeat the diagnosis after one or two weeks and additionally consult a geneticist.

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Analysis of AFP in pregnancy

The analysis of AFP during pregnancy also falls into the category of mandatory tests. Pregnant women are prescribed this analysis in order to exclude the possibility of development of chromosomal abnormalities in the baby, neural tube defects, as well as abnormalities of the internal organs and extremities. It is advisable to carry out diagnostics within 12-20 weeks, but the most accurate information can be obtained at 14-15 weeks.

The fetal AFP begins to be produced from 5 weeks, respectively, on each subsequent week the percentage of AFP in the mother's blood increases, reaching a maximum at 32-34 weeks. The norm for the index is 0.5-2.5 MoM. If the indicator is higher than the norm, this can mean:

  • An error in determining the duration of pregnancy.
  • There is a multiple pregnancy.
  • Problems with the kidneys.
  • Hernia of the navel in the fetus.
  • Anomalies of the nervous column.
  • Abnormalities of the abdominal wall.
  • Other physiological malformations.

If the AFP index is underestimated, the probability of Down's syndrome, hydrocephalus, trisomy, gall bladder drift, other chromosomal abnormalities, developmental delay and intrauterine fetal death are high.

It is not worthwhile to rely entirely on the indexes of AFP in the blood, according to the indicators of analysis, it is impossible to put a full-fledged diagnosis, so one should not despair and be upset. At any deviations from the norm in more than 90% of cases, healthy children are born.

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Analysis of PAPP-A in pregnancy

The analysis of PAPP-A in pregnancy is carried out in the first trimester, in order to reveal the degree of risk of the birth of a child with chromosomal abnormalities. The level of PAPP-A in the mother's blood decreases with chromosomal abnormalities, with the threat of miscarriage, pregnancy fading. The analysis is carried out starting from week 8, but the most optimal dates are 12-14 weeks. After this term, the reliability of the result is much reduced. The most accurate result can be obtained if you perform a comprehensive examination - an analysis of hCG level, PAPP-A level and examination of the collar zone of the fetus using ultrasound.

Analysis of the rat-a during pregnancy is prescribed for pregnant women who:

  • Have an anamnesis pregnancy with complications.
  • They are over 35 years old.
  • Have an anamnesis of two or more spontaneous abortions.
  • Have a history of pre-conception or early pregnancy viral and infectious diseases.
  • They have a baby with chromosomal abnormalities in the family.
  • They have severe hereditary pathologies in the genus.
  • Before pregnancy, parents were exposed to radiation.

An increase in the content of PAPP-A indicates a high risk of chromosomal pathologies in the future baby (deviations in 21 and 18 pairs of chromosomes and other abnormalities), a high probability of pregnancy fading and spontaneous abortion.

Genetic analysis during pregnancy helps to diagnose the pathology of the fetus in the early stages, and the timely beginning of treatment to keep the pregnancy and the health of the baby.

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