Down syndrome births in the United States from 1989 to 2001.
OBJECTIVE
We investigated the observed and expected Down syndrome livebirths in the US from 1989 to 2001.


METHODS
Using birth certificate data, we recorded maternal age-specific live births from 1989 to 2001, and stratified them by women 15 to 34 and 35 to 49 years old. We estimated Down syndrome live births from 1989 to 2001, assuming no terminations. We recorded Down syndrome live births by year from 1989 to 2001.


RESULTS
Despite an expected 1.32-fold increase in Down syndrome live birth rates from 1989 to 2001, Down syndrome live births actually declined. In 1989, the rate of Down syndrome cases was 15% lower than expected, decreasing to 51% by 1998. Women 15 to 34 had 45% fewer affected pregnancies in 2001, while women 35 to 49 had 53% fewer in 2001. We estimated that Down syndrome live births decreased from 3962 in 1989 to 3654 in 2001.


CONCLUSIONS
Down syndrome live births declined in the US despite an expected increase caused by delayed or extended childbearing.
Department of Obstetrics and Gynecology, University of Connecticut Health Center, Farmington, USA.
James F X
JF
Egan
Peter A
PA
Benn
Carolyn M
CM
Zelop
Alan
A
Bolnick
Elisa
E
Gianferrari
Adam F
AF
Borgida
D000293:Adolescent; D000328:Adult; D004314:Down Syndrome / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008423:Maternal Age; D008875:Middle Aged; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D014481:United States / Q000453:epidemiology