MATERNAL SERUM LEVELS OF FREE BETA-HCG AND PAPP-A IN THE FIRST-TRIMESTER OF PREGNANCY ARE NOT ASSOCIATED WITH SUBSEQUENT FETAL GROWTH-RETARDATION OR PRETERM DELIVERY

The purpose of this case-control study was to examine the association of first-trimester concentrations of free beta-human chorionic gonadot ropin (free beta-hCG) and pregnancy-associated plasma protein A (PAPP- A) in maternal serum with subsequent preterm delivery or small-for-ges tational age (SGA) fetuses. We collected all the blood samples before chorionic villus sampling in the first trimester. Concentrations of fr ee beta-hCG and PAPP-A were expressed in multiples of the median (MOM) for gestational age. We compared the levels of both analytes in 73 SG A pregnancies (birth weight below the fifth percentile) with those in 292 normal controls, who were matched for gestational age, maternal ag e, parity, maternal weight, and smoking habits. We also compared the l evels in 87 pregnancies with a preterm delivery (delivery before 37 co mpleted weeks) with those in 348 matched controls. The median concentr ations of PAPP-A and free beta-hCG, expressed in MOMs, in the 73 SGA p regnancies were 0.83 and 0.95, respectively, compared with 0.98 and 1. 01, respectively, in the 292 matched controls (P=0.08 and 0.19, respec tively). In the 87 pregnancies with a preterm delivery, the median con centrations of PAPP-A and free beta-hCG were 0.98 and 0.94, respective ly, compared with 0.99 and 0.99, respectively, in the 348 matched cont rols (P=0.82 and 0.10, respectively). In contrast with the maternal se rum analytes used in second-trimester screening-alpha-fetoprotein and human chorionic gonadotropin-this study showed that concentrations of PAPP-A and free beta-hCG in the first trimester were not associated wi th subsequent fetal growth retardation or preterm delivery. (C) 1998 J ohn Wiley & Sons, Ltd.