A review of the diagnostic test for amniocentesis during pregnancy

A review of the diagnostic test for amniocentesis during pregnancy

Amniocentesis is a prenatal diagnostic procedure in which a small amount of amniotic fluid is extracted and often sent to a genetic lab to check for chromosomal abnormalities.

Amniotic fluid is the fluid that surrounds the fetus, and as the fetus grows, cells separate from its body and enter the amniotic fluid.

By examining the embryonic cells in the amniotic fluid, which have the same genetic composition as the fetus, it is possible to diagnose genetic disorders in different ways (including conventional full-karyotype, high-resolution full karyotype, Array CGH, etc.).

• In what cases is amniocentesis necessary?

1) The mother is over 35 years old at the time of delivery

2) Abnormal levels of biochemical markers in screening tests

3) Abnormal results in ultrasound

4) The possibility of detecting a type of genetic disease in the fetus (provided that the type of disorder and its mutation is diagnosed and confirmed before pregnancy or at the beginning of pregnancy)

5) Presence of a history of neural tube defects (NTD) in previous pregnancies

6) Existence of chromosomal abnormalities (such as Down syndrome) in previous pregnancies

7) In cases where the parents are chromosomal abnormalities.

The most common test for amniotic fluid is chromosomal abnormalities.

However, in addition to chromosomal abnormalities, it is possible to diagnose single gene disorders by amniocentesis.

In such cases, the condition of the parents and the type of mutation must be determined before pregnancy (or at the beginning of pregnancy) so that we have enough time to perform these steps.

Other uses for amniocentesis include the detection of neural tube defects (such as spina bifida and anencephaly) by measuring the alpha levels of amniotic fluid phytoprotein.

• Suitable time for amniocentesis: The best time to have amniocentesis is from the 14th to the 20th week of pregnancy.

However, if necessary, it can be done after this time.

However, due to the fact that in Iran only in pregnancies of less than four full months (19 weeks) the license to terminate a pregnancy is issued by forensic medicine, it is recommended that this test be performed before the end of the 16th week.

- How to do it: Amniocentesis is an outpatient procedure and does not require hospitalization, and the pregnant woman will go home immediately after sampling.

- You do not need to fast to do it and it is often recommended that the mother eat a light meal.

The whole process takes about 15-20 minutes and the drawing usually takes less than a minute. Recommended ,

Recommendations for preventing abortion in amniocentesis:

1- Absolute rest for at least 3 days