3) First-trimester screening 孕早期筛查4) First trimester screening 早孕期筛查5) second trimester screening 孕中期筛查6) Prenatal screen 产前筛查 1. Prenatal screen and diagnose of Down syndrome.; 唐氏综合征产前筛查与诊断 2. This article makes a comprehensive analyses about the recognition,...