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Original Contribution
April 15, 1983

Chromosomal Abnormality Rates at Amniocentesis and in Live-Born Infants

Author Affiliations

From the Bureau of Maternal and Child Health, State of New York Department of Health (Dr Hook, Mr Cross, and Ms Schreinemachers), and the Department of Pediatrics, Albany Medical College (Dr Hook), Albany, NY.

JAMA. 1983;249(15):2034-2038. doi:10.1001/jama.1983.03330390038028

Regression-smoothed maternal age-specific rates of six different categories of cytogenetic abnormalities in recent large-scale prenatal cytogenetic studies were multiplied by independently derived fetal selection coefficients—factors that adjust for the excess likelihood of spontaneous loss of cytogenetically abnormal fetuses—to obtain estimated maternal age-specific rates of these categories of cytogenetic abnormalities in live-born infants. The derived rates apply to women whose only risk factor is advanced maternal age. The categories analyzed were 47,+21 (Down's syndrome), 47,+18 (Edwards' syndrome), 47,+13 (Patau's syndrome), 47,XXY (Klinefelter's syndrome), 47,XXX, and the group of other clinically significant abnormalities considered collectively. The rate of all clinically significant abnormalities considered together derived in this study was about five per 1,000 at age 35 years, 15 per 1,000 at age 40 years, and 50 per 1,000 at age 45 years.

(JAMA 1983;249:2034-2038)

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