Department of Obstetrics & Gynecology, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA. bahadoro@ucmail.uc.edu
This article discusses biochemical screening for congenital defects. Biochemical screening remains the standard for estimating the risk of aneuploidy in pregnancy. The combination of first and second trimester markers promises to further improve diagnostic accuracy for anomaly detection.