All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Alpha fetoprotein test in pregnancy
Medical expert of the article
Last reviewed: 04.07.2025
An alpha-fetoprotein (AFP) test during pregnancy is performed to detect developmental defects in the unborn child.
AFP is produced by the yolk sac of the embryo, starting from the 5th week, and its maximum percentage is determined in the mother's blood already at 32-33 weeks, the normal concentration is from 25 to 55 IU/ml. In the body of the future child, this protein takes on the following functions:
- Maintenance of oncotic blood pressure.
- Blocking and neutralizing maternal estrogens.
- Intrauterine protection from maternal immunity.
- Transportation of substances into the body of the unborn child.
The analysis is carried out in parallel with the study of the level of hCG and estriol, to obtain the most accurate results. The most suitable time for the analysis is 16-18 weeks. Indications for the analysis are as follows:
- Pregnant woman over 35 years old.
- The pregnant woman is married to a blood relative.
- There are cases of chromosomal abnormalities in the family that are inherited.
- The family already has a child with chromosomal abnormalities.
- Previous pregnancies ended in stillbirth, miscarriage, and frozen pregnancy.
- In the early stages of pregnancy, the woman was exposed to radiation and toxins.
- In the early stages, drugs were taken that had a toxic effect on the embryo.
- X-rays were performed in the early stages of pregnancy.
[