Free beta and hCG in Screening for Down Syndrome

摘要

Approximately two-thirds of the 4.1 million annual pregnancies in the UnitedStates are screened prenatally for fetal Down syndrome. Most women are screened using alphafetoprotein (AFP), unconjugated estriol (uE3), and human chorionic gonadotropin (hCG). An estimated 60-70% of cases of Down syndrome can be detected with an initial positive rate of 5 to 8% with the three marker combination.