Risk of miscarriage in women with endometriosis: insights from in vitro fertilization cycles

Objective: To evaluate whether women with endometriosis achieving singleton pregnancies with IVF face an increased risk of miscarriage. Design: Matched case-control study. Setting: Infertility units. Patient(s): Women achieving singleton pregnancies with the use of IVF were considered. Cases were women with a history of surgery for endometriosis and those who were documented the presence of ovarian endometriomas at the time of the IVF cycle (n = 313). Controls were matched to cases by age (±6 months), type of cycle (fresh or frozen cycle). and study period (n = 313). Intervention(s): Retrospective review of women undergoing IVF. Main Outcome Measure(s): Rate of miscarriage before 12 weeks' gestation. Result(s): The number of miscarriages in women with and without endometriosis was similar, being 48 (15%) and 60 (19%), respectively. The odds ratio of miscarriage in affected women was 0.76 (95% confidence interval 0.50-1.16). The odds ratio adjusted for body mass index (BMI), parity, duration of infertility, and male factor infertility was 0.81 (95% confidence interval 0.53-1.25). Subgroup analyses according to the type of cycle, the number of embryos transferred, the presence of endometriomas, and the history of surgery for endometriosis did not document any subgroup at significant increased risk of miscarriage. Conclusion(s): The risk of miscarriage is not increased in women with endometriosis achieving pregnancy with the use of IVF.