The predictive value of maternal serum AFP to PAPP-A or b-hCG ratios in spontaneous preterm birth

Abstract

The use of the second trimester alpha-fetoprotein (AFP) along with the first trimester pregnancy-associated plasma protein-A (PAPP-A) has been found to be useful in the estimation of unfavourable pregnancy outcome. Our aim in this study was to determine the relationship between maternal PAPP-A and b-hCG and AFP concentrations in spontaneous preterm birth (sPTB). This prospective cohort study included 372 singleton pregnancies with PAPP-A, b-hCG and AFP levels in the first trimester, which were converted to multiples of the median (MoM). The predictive ability of AFP-to-PAPP-A and AFP-to-b-hCG ratios for sPTB was evaluated. The risk for sPTB <= 34 weeks increased in women with AFP-to-PAPP-A ratio >7 (OR 2.9, 95% CI 1.2-6.4). Women with AFP-to-b-hCG ratio >0.6 had a 3.5-fold higher risk for sPTB <= 32 weeks. Increased maternal AFP-to-PAPP-A or AFP-to-b-hCG ratios in the first trimester may help to predict pregnant women at high risk for sPTB, and this may be beneficial in developing management plans.