Frontonasal Fold Thickness–to–Nasal Bone Length Ratio as a Prenatal Sonographic Marker for Trisomy 21 in a Low-Risk Population

Received June 12, 2012, from the UltrasoundUnit, Pedro Aguirre Cerda Primary HealthcareCenter, Santiago, Chile (R.G.); Department ofObstetrics and Gynecology, Luis Tisne BrousseHospital, University of Chile School of Medicine,Santiago, Chile (S.A.); Department of Obstetricsand Gynecology, Barros Luco-Trudeau Hospital,Santiago, Chile (V.D.); and Fetal MedicineCenter, Fetal Medicine Interest Group GIMEF,Santiago, Chile (W.S.). Revision requested July 9,2012. Revised manuscript accepted for publicationSeptember 25, 2012.This work was presented at the 11th WorldCongress in Fetal Medicine; June 24–28, 2012;Kos, Greece. Dr Sepulveda was supported by anunrestricted research grant from the SociedadProfesional de Medicina Fetal “Fetalmed” Limi-tada, Chile.Address correspondence to Waldo Sepulveda,MD, Fetal Medicine Center, Casilla 208, San-tiago 20, Chile.E-mail: fetalmed@yahoo.com