Increasing parity heightens the risk for having a child with Down syndrome.

2003 NOV 6 - (NewsRx.com & NewsRx.net) -- Increasing parity heightens the risk for having a child with Down syndrome.

"Interpretation of studies that have examined parity as a risk factor for Down syndrome has been hindered by inadequate control for maternal age and/or failure to account for the differential use of prenatal diagnosis and pregnancy termination between low-parity and high-parity women.

"In this case-control study, the authors used exact matching on maternal age-minimize confounding and evaluated the potential impact of differential termination. A total of 898 cases of Down syndrome and 4488 controls were identified using Washington State birth certificates from 1984-1998," scientists in the United States reported.

"There was a trend towards increasing risk of Down's syndrome with increasing parity in both younger (age

"After restriction, odds ratios were as high as 1.65 (95% confidence interval: 1.13, 2.40) in younger women with a parity of three (compared with a parity of zero) and 2.41 (95% confidence interval: 1.41, 4.12) in older women with a parity of four or more. Although the odds ratios for older women were probably biased upwards because of underreporting of amniocentesis on ...