Affect of late-onset prenatal care on antenatal diagnosis.
D001719:Birth Certificates; D000013:Congenital Abnormalities / Q000453:epidemiology*; D004282:Documentation; D004314:Down Syndrome / Q000453:epidemiology; D005260:Female; D006801:Humans; D011247:Pregnancy; D011295:Prenatal Care; D011296:Prenatal Diagnosis; D014768:Virginia