Adverse pregnancy outcomes after abnormal first-trimester screening for aneuploidy.

Women with abnormal results of first trimester screening but with a normal karyotype are at risk for adverse pregnancy outcomes. A nuchal translucency of greater than 3.5 mm is associated with an increased risk of subsequent pregnancy loss, fetal infection, fetal heart abnormalities, and other structural abnormalities. Abnormal levels of first trimester analytes are also associated with adverse pregnancy outcomes, but the predictive value is less impressive. As a single marker, pregnancy-associated plasma protein (PAPP)-A level less than 1st percentile has a good predictive value for subsequent fetal growth restriction. Women with PAPP-A level less than 5th percentile should undergo subsequent risk assessment with routine maternal serum afetoprotein screening with the possible addition of uterine artery pulsatility index assessment in the midtrimester.