Screening for the risk of fetal aneuploidy can be effectively performed in either the first or second trimester. When obtained independently, the interpretation of those data is straightforward. However, the effectiveness of screening can be enhanced by combining studies performed in each trimester in a variety of ways. In this commentary we will define and discuss both the advantages and disadvantages of using integrated, stepwise, sequential or contingency screening for risk assessment of fetal aneuploidy.
The effectiveness of screening for fetal aneuploidies can be enhanced by combining firstand second-trimester studies in different ways.
From the 1Department of Obstetrics and Gynecology, Columbia University College of Physicians and Surgeons, New York, New York; and the 2Department of Reproductive Epidemiology, School of Medicine, University of Leeds, United Kingdom.
Corresponding author: Richard L. Berkowitz, MD, Department of Obstetrics and Gynecology, Columbia University College of Physicians and Surgeons, 622 West 168th Street, New York, NY 10128; e-mail: email@example.com.