Excess Weight Lowers Embryo Implantion Rates


WASHINGTON — Overweight and obese women had significantly lower embryo implantation rates than did normal-weight women, according to data from 1,870 women who underwent in vitro fertilization.

Results from recent studies suggest that weight has an impact on both fertility and pregnancy, with implications not only for prospective mothers but also for their infants.

In this study, Darlene M. Davies and her colleagues at the Fertility Centers of New England in Reading, Mass., reviewed data from 1,870 patients younger than 42 years of age who underwent IVF with intracytoplasmic sperm injection (ICSI) between January 2004 and December 2006.

Women who were classified as overweight (BMI 25–29.9 kg/m

In addition, the percentage of embryos consisting of seven to eight cells on the third day after embryo transfer—a sign of a high-quality embryo—was significantly lower in the most obese women with a BMI of 35–39.9, compared with women with a BMI of 30–34.9 (34% vs. 40%).

The findings, presented in a poster at the annual meeting of the American Society for Reproductive Medicine, support data from previous studies in which women with a BMI of 25 or higher required more gonadotropins, were less likely to become pregnant, and were more likely to miscarry, compared with women with a BMI of 25 or lower (Hum. Reprod. Update 2007;13:433–44), the investigators noted.

In addition, the percentage of spontaneous abortions, though not significantly higher, was higher in the most obese women (BMI 35–39.9), compared with all other weight groups (6% vs. 4%).

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