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In vitro fertilization doubles the risk of preeclampsia during pregnancy for women expecting more than one child

Techniques to assist conception have dramatically increased the number of multiple births. However, women who achieve pregnancy with more than one child by in vitro fertilization or gamete intrafallopian transfer have a two-fold higher risk of preeclampsia than women who conceive spontaneously, according to a study supported by the Agency for Healthcare Research and Quality (HS10700).

Preeclampsia usually occurs in late pregnancy and is characterized by high blood pressure and abnormal metabolism that in serious cases can lead to coma and death. Preeclampsia or eclampsia complications account for almost 20 percent of pregnancy-related maternal deaths.

Anne Lynch, M.D., M.S.P.H., of Kaiser Permanente in Denver, CO, and her colleagues compared the risk of preeclampsia among women who conceived a multiple gestation as a result of assisted conception with women who conceived spontaneously by examining a total of 525 multiple gestations from a Colorado health maintenance organization from 1994 to 2000. Of the total, 69 multiple gestations followed assisted reproductive technologies (in vitro fertilization or gamete intrafallopian transfer). So-called fertility drugs—human menopausal gonadotropins and clomiphene citrate—were associated with 38 and 91 of the multiple gestations, respectively.

Overall, 18 percent of mothers developed preeclampsia. Women whose conceptions were assisted by reproductive technologies (75 percent of whom were over 35 years of age) had nearly three times the relative risk of mild preeclampsia and nearly five times the risk of severe preeclampsia compared with women who had spontaneous conceptions.

After adjustment for maternal age and number of pregnancies, women who received assisted reproductive technologies were two times more likely to develop preeclampsia compared with those who conceived spontaneously. The incidence of preeclampsia was greater in mothers who received the fertility drugs, but this association was not significant.

See "Preeclampsia in multiple gestation: The role of assisted reproductive technologies," by Dr. Lynch, Robert McDuffie, Jr., M.D., James Murphy, Ph.D., and others, in the March 2002 Obstetrics & Gynecology 99(3), pp. 445-451.

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