Prospective validation of first-trimester combined screening for trisomy 21.

The article presents a prospective study that combines maternal age, fetal nuchal translucency (NT) and maternal serum freeβ-human chorionic gonadotropin (β-hCG) , and pregnancy-associated plasma protein-A (PAPP-A) in screening for trisomy 21. It presents the characteristics of 19, 614 pregnancies with normal delivery and 122 cases of trisomy 21, which comprise the study population. It reveals that the capability of the combine method to detect 90% for trisomy 21.