The effect of estimating gestational age by ultrasound cephalometry on the sensitivity of alpha-fetoprotein screening for Down's syndrome.
D002508:Cephalometry; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011296:Prenatal Diagnosis; D014463:Ultrasonography; D000509:alpha-Fetoproteins / Q000032:analysis*
D000509:alpha-Fetoproteins