Endometriosis and spontaneous hemoperitoneum in pregnancy: evaluation of the magnitude of the risk in women becoming pregnant via in vitro fertilization

Objective: To estimate the frequency of spontaneous hemoperitoneum in pregnancy (SHiP) in women with endometriosis achieving pregnancy with in vitro fertilization (IVF). Design: Retrospective case series. Setting: Referral academic assisted reproductive technology (ART) center. Patient(s): Three hundred and forty-eight women with a history of surgery for endometriosis and women with ovarian endometriomas or deep endometriotic nodules detected at basal transvaginal ultrasound performed before IVF cycle. Intervention(s): Information obtained from patients' charts on basal characteristics, IVF cycle, and pregnancy outcomes, and binomial distribution model created to determine the 95% confidence interval (CI) of the proportion of SHiP. Main outcome measure(s): Rate of SHiP. Result(s): Overall, 362 pregnancies were included, among which 238 (66%) had a history of previous surgery for endometriosis and 231 (64%) had endometriosis detected at ultrasound (107 women, 30%, had both). Pregnancies were achieved after fresh and frozen cycles in 244 (67%) and 118 (33%) women, respectively. One case of SHiP was recorded, corresponding to a rate of 0.3%. Conclusion(s): In the general population of women with endometriosis undergoing IVF, SHiP is uncommon. Future studies should better identify the risk factors for SHiP to disentangle the subgroups of women at higher risk.