Is the ratio of maternal serum to amniotic fluid AFP superior to serum levels as a predictor of pregnancy complications?

Purpose: The use of maternal serum alpha fetoprotein (MSAFP) levels as a predictor of pregnancy complications (PC) is well established. We hypothesized that the ratio between the MSAFP/AFAFP levels (RATIO) will more accurately predict PC than MSAFP levels alone. Methods: Women who had a MSAFP test followed by amniocentesis were divided into two groups: those who had PC comprised the study group and those who had an uneventful pregnancy served as the control group. Data regarding pregnancy and delivery course were collected. The RATIO between the study and the control groups was compared. Results: 166 women were included in the study, of which 24 had PC. A significant correlation was found between the RATIO and intrauterine growth restriction (IUGR) and week of delivery. Six pregnancies had elevated MSAFP levels; two with RATIO below 2 had uneventful pregnancies. Among the other four pregnancies with RATIO above two, one had IUGR and the other, placental abruption. Conclusion: Our data suggest that the RATIO might serve as a predictor of IUGR and week of delivery. Although the number of patients in the current study was relatively small, the novelty of the proposed simple marker implies that a larger scale study is warranted. Such studies may confirm this finding and a possible advantage of using this RATIO instead of or in addition to MSAFP values for better prediction of pregnancies at risk for PC.