Detection Rate and Sonographic Signs of Trisomy 21 Fetuses at 14-17 Weeks of Gestation.

Background: Early prenatal ultrasound is an important part of prenatal screening in Israel. No studies have described the rate of trisomy 21 [T21] identification at 14-17 weeks gestation.

Objectives: To describe the rate of T21 identification by transvaginal sonograms (TVS) at 14-17 weeks gestation.