Influence of selected factors on serum AFP levels in pregnant women in terms of prenatal screening accuracy — literature review

Alpha-fetoprotein (AFP) is one of the biochemical components of the triple (T-3) and quadruple (T-4) test used so far in prenatal screening mainly for trisomy 21 (T21) and neural tube defects (NTDs). Based on many years of experience and data collected during these studies, a variety of factors have been identified that can affect a pregnant woman's serum AFP level, and thus the risk assessment of trisomy 21 (T21) and neural tube defects. These include both unaccounted for purely medical data (e.g., from baseline information about the patient, assisted reproduction methods used, comorbidities and emerging pregnancy pathologies) and errors made during statistical analysis. Since the triple or quadruple test is usually performed between 15 and 20 weeks of pregnancy, most scientific studies are based solely on results from this period of pregnancy — limited data are available for the first and third trimesters of pregnancy. In the era of new improved screening tests, AFP has the potential to become an independent marker for pregnancy well-being evaluation

Alpha-fetoprotein (AFP) — new aspects of a well-known marker in perinatology

Alpha-fetoprotein (AFP) is a serum protein, which is characteristic of the fetal development period and a well-known oncological marker. The predominance of AFP among serum proteins is common in fetal life, whereas after birthing its functions are gradually taken over by albumins. An understanding of the mechanism of AFP transfer between fetus and mother has led to the development of screening tests for identifying neural tube defects and Down’s syndrome. Currently, the knowledge on patophysiology and the possible importance of AFP in perinatology and fetal medicine extends far beyond those 2 disease states. Throughout the 50 years of research on AFP, there has been dynamic progress of diagnostic techniques, from the qualitative ones that are used solely for scientific studies to the widely used radioimmunoassays and immunoenzymatic assays (enzyme-linked immunosorbent assay, chemiluminescence immunoassay, time-resolved fluorescence immunoassay). Some genetic mutations cause complete inhibition of AFP production by the fetus. This affects the results of screening tests during pregnancy, and also leads to constantly high levels of AFP in adults, which are not linked to oncogenesis.