First‐trimester biochemical markers for Down syndrome

The value of maternal serum pregnancy-associated protein A (PAPP-A), free and total β human chorionic gonadotrophin (fβhCG, βhCG) and α-fetoprotein (AFP) in screening for Down syndrome (DS) in early pregnancy has been assessed. To evaluate the different biochemical markers, 32 DS pregnancies and 267 controls were used for AFP, βhCG and PAPP-A. A subgroup of those (17 DS and 136 controls) were used to evaluate fβhCG. All analytes were determined in fresh serum samples. Our results give support to the feasibility of maternal serum levels of PAPP-A as the best biochemical marker for DS in the first trimester, and either βhCG or fβhCG as the second marker. No differences were found between βhCG and fβhCG distribution levels as expressed as MoMs in normal and DS pregnancies in this study. Copyright © 1999 John Wiley & Sons, Ltd.