Alpha-fetoprotein (AFP) is an embryonic protein reproduced by the fetal liver and gastrointestinal tract, which is usually present in the blood and amniotic fluid of pregnant women. High or low levels of alpha-fetoprotein can be associated with certain congenital malformations, such as Edwards syndrome, Down syndrome, anencephaly, spina bifida, etc. Test AFP will help identify abnormalities in the fetus.
What is an AFP test?
During the period from the 15th to the 20th week of pregnancy, many pregnant women are recommended to perform invasive perinatal diagnostics, which often causes shock in them. One of the most sparing methods that do not require internal penetration is the AFP test, which determines alpha-fetoprotein during pregnancy in the mother’s blood. Blood is taken from the mother’s vein and sent to the laboratory for analysis. The result, which usually becomes known after 1-2 weeks, is compared with the age of the mother and her ethnicity in order to assess the likelihood of potential genetic disorders.
This test gives the most accurate indicators from 16 to 18 weeks. Due to the fact that alpha-fetoprotein changes its concentration level during pregnancy, an accurate date of conception is necessary for more reliable examination results. However, it must be taken into account that the test results are not a diagnosis, but only signal that further diagnosis is needed to identify congenital malformations in the fetus.
Who is recommended for test AFP?
Of course, it is desirable that all pregnant women carry out such an examination. However, it is mandatory to determine alpha-fetoprotein during pregnancy for women who:
- have a family history of birth defects;
- over 35 years old;
- took various drugs or drugs during pregnancy;
- suffer from diabetes.
If alpha-fetoprotein is elevated, this may indicate that the developing fetus has a neural tube defect, such as cleft spine or anencephaly, kidney and urinary tract abnormalities, and other congenital malformations. High levels of alpha-fetoprotein may also suggest birth defects in the esophagus. However, the most common cause of elevated AFP levels is inaccurate dating of pregnancy.
If alpha-fetoprotein is underestimated during pregnancy, and abnormal levels of hCG and estriol are observed, this may indicate that the developing fetus may have a developmental delay, trisomy 18 (Edwards syndrome), trisomy 21 (Down syndrome), or another type of chromosomal abnormality.
AFP Test Results
It is important to remember that the AFP test is not a diagnostic test, it only notes that the fetal health is at risk. If abnormal levels of alpha-fetoprotein are detected, additional testing is required to make an accurate diagnosis. A more conservative approach involves conducting a second AFP test or 3D ultrasound. If repeated testing confirms that alpha-fetoprotein during pregnancy (AFP rate is calculated depending on the gestational age) is too high or too low, more invasive procedures, such as amniocentesis, are prescribed.
Although alpha-fetoprotein testing is not performed for all pregnant women, in some cases this is necessary. Moreover, in addition to the discomfort when taking blood, there are no risks and side effects associated with its conduct. This is a normal test, which does not involve internal penetration, and therefore does not pose a danger to the mother or child. If the test is not offered, the woman herself can insist on carrying it out (if, of course, she believes that it can be useful for her and her baby) to make sure the pregnancy is normal.