The role of second-trimester serum screening in the post-first-trimester screening era.

摘要

Considerable advances have been made in identifying women whose pregnancies are at the greatest risk for fetal Down syndrome and other aneuploidies. Maternal serum tests and ultrasonography in either the first or second trimester provide effective prenatal screening. However, the most efficacious protocols are based on the combination of first- and second-trimester tests. In this article the advantages and best strategies in providing these sequential screening protocols are discussed.