Screening for trisomy 21 in Flanders: a 10 years review of 40.490 pregnancies screened by maternal serum.

Objective: To evaluate maternal serum screening for trisomy 21 (MSS) in Flanders between 1992 and 2002.

Study Design: Data of a large database on the results of MSS, nuchal translucency (NT) and pregnancy outcome were analysed retrospectively.

Results: Despite an excellent performance of second trimester MSS at a maternal age > or = 35 years (94.