FETAL GENDER IMPACT ON MULTIPLE-MARKER SCREENING RESULTS

Maternal serum alpha-fetoprotein (MSAFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3) are used in combination with ma ternal age to calculate the risk for Down syndrome (DS) in pregnancy, Increased levels of hCG and decreased levels of MSAFP and uE3 are cons istent with an increased risk for DS, We retrospectively evaluated sec ond-trimester maternal serum marker levels in a large cohort of patien ts with known normal outcomes and documented fetal gender, These inclu ded 15,428 patients who had MSAFP measurements, 11,428 patients with b oth MSAFP and hCG, and 6,090 patients with all three markers including uE3, MSAFP levels in patients with female fetuses were consistently l ower than those with males, Conversely, hCG was higher in pregnancies with females as compared to males, No gender-related difference was no ted for uE3. These results would suggest that the computed DS risk for female fetuses is higher than for males, despite the fact that the in cidence of DS is similar in both genders, This information could be us eful for calculating gender-specific DS risk; however, this would requ ire ultrasonographic determination of fetal sex. (C) 1998 Wiley-Liss, Inc.