Nuchal translucency screening and antenatal maternal serum screening for Down syndrome: results of a project

Abstract

Objectives: To asses the implementation of antenatal screening for Down syndrome using individual risk estimates based on maternal age, nuchal translucency and three serum markers; alpha fetoprotein, unconjugated estriol and human chorionic gonadotrophin (hCG) in maternal blood. Women with an estimated risk of 1 in 250 or greater were classified as screen positive and offered diagnostic amniocentesis.Subjects: A total of 1956 women of all ages with singleton pregnancies seen between June 1999 and March 2001.Results: The screening result of combination of first trimester ultrasonographic and serum screening was 85% Down syndrome detection and the false positive rate was 3%. The median gestational age of nuchal translucency was 11 weeks and the time of serum screening was 16 weeks.Conclusion: The combination of nuchal translucency and serum screening increases the Down syndrome detection and decreases the false positive rate. Is very important because the amniocentesis is associated with a risk of pregnancy loss from 0.5 to 1%. Besides, it is cost‐effective and performs better than the selection for amniocentesis on the basis of maternal age only, nuchal translucency only or serum screening.