Gestational hypertension in pregnancies supported by infertility treatments: role of infertility, treatments, and multiple gestations

ObjectiveTo investigate the association between infertility treatments and gestational hypertension and preeclampsia.DesignRetrospective observational cohort.SettingGeneral population, United States and Canada.Patient(s)Five thousand one hundred fifty-one women with nonmalformed infants participating in the Slone Epidemiology Center Birth Defects Study between 1998 and 2006.Intervention(s)Women were interviewed within 6 months after delivery about sociodemographic and medical factors, about the onset of gestational hypertension and preeclampsia, and about infertility treatments.Main Outcome Measure(s)We estimated relative risks and 95% confidence intervals by using unconditional logistic regression.Result(s)The incidence of gestational hypertension was 8.9% (423/4,762) among women without infertility treatments and was 15.8% (55/349) among women undergoing infertility treatments. Compared with spontaneous pregnancies, the crude relative risk for gestational hypertension in pregnancies resulting from infertility treatments was 1.9 (95% confidence interval, 1.4–2.6). Multivariate adjustment for parity and prepregnancy body mass index resulted in a relative risk of 1.6 (1.1–2.1). Further adjustment for multiple pregnancies, or restriction of the analyses to singleton pregnancies, moved the relative risk to 1.3. Each specific infertility procedure or drug was associated with a similarly elevated risk, which disappeared after adjustment for multiple gestations. Results were similar for preeclampsia.Conclusion(s)Pregnancies resulting from infertility treatments have a higher incidence of gestational hypertension and preeclampsia than do spontaneous conceptions. This increased risk is largely explained by the higher frequency of multiple gestations.