Demographic differences in Down syndrome livebirths in the US from 1989 to 2006

Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Connecticut Health Center, Farmington, CT 06030, USA.
Prenatal Diagnosis (Impact Factor: 3.27). 04/2011; 31(4):389-94. DOI: 10.1002/pd.2702
Source: PubMed


To explore demographic differences in Down syndrome livebirths in the United States.
Using National Center for Health Statistics (NCHS) birth certificate data from 1989 to 2006 we analyzed Down syndrome livebirths after correcting for under-reporting. We created six subsets based on maternal age (15-34 and 35-49 years old); US regions, that is, Northeast, Midwest, South and West; marital status, (married, unmarried); education, ( ≤ 12 years, ≥ 13 years); race, (white, black); and Hispanic ethnicity, (non-Hispanic, Hispanic). We estimated expected Down syndrome livebirths assuming no change in birth certificate reporting. The percentage of expected Down syndrome livebirths actually born was calculated by year.
There were 72 613 424 livebirths from 1989 to 2006. There were 122 519 Down syndrome livebirths expected and 65 492 were actually born. The Midwest had the most expected Down syndrome livebirths actually born (67.6%); the West was lowest (44.4%). More expected Down syndrome livebirths were born to women who were 15 to 34 years old (61 vs 43.8%) and to those with ≤ 12 years education (60.4 vs 46.9%), white race (56.6 vs 37%), unmarried (56.0 vs 52.5%), and of Hispanic ethnicity (55.0 vs 53.3%).
The percentage of expected Down syndrome livebirths actually born varies by demographics.

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    • "Currently, prenatal screening tests are widely offered by antenatal clinics to pregnant women over 35 years of age who are at greater risk. Despite the success of these screening programmes up to 61% of all infants with Down syndrome are born to women under the age of 35 who are not routinely offered testing [4]. By maternal serum screening, in combination with ultrasound assessment of nuchal translucency, approximately 90% of all Down syndrome pregnancies can be detected [5]. "
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