(Abstracted from Ultrasound Obstet Gynecol 2018;52(3):318–324)
Increased use of fertility treatment and advanced maternal age contribute to the increased prevalence of twin pregnancy, which is currently approximately 3% in the United States. Screening for trisomy 21 in twins largely relies on maternal age and nuchal translucency measurement in the first trimester, as well as first- and second-trimester serum screening.
Service de Gynécologie-Obstétrique et Médecine de la Reproduction, Hôpital Antoine Béclère, Assistance Publique-Hôpitaux de Paris, Clamart (G.L.C., A.L., A.B.); Université Paris Sud, Kremlin Bicêtre (G.L.C., A.L., A.B.), France; Department of Obstetrics and Gynecology, University Hospital Brugmann, Université Libre de Bruxelles, Brussels, Belgium (J.J.); and Laboratoire CERBA, Saint-Ouen l'Aumône, France (P.K., L.L., J.-M.C.)