Collaborative study of Down syndrome screening using maternal serum alpha-fetoprotein and maternal age.
D002986:Clinical Trials as Topic; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008423:Maternal Age; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012306:Risk; D000509:alpha-Fetoproteins / Q000032:analysis*
D000509:alpha-Fetoproteins