Complications of the third stage of labor in in vitro fertilization pregnancies: an additional expression of abnormal placentation?

Objective: To assess the correlation between in vitro fertilization (IVF) and complications of the third stage of labor. Design: Retrospective cohort of vaginal deliveries from November 2008 to January 2020. Maternal and obstetric outcomes of singleton deliveries were compared between IVF and non-IVF pregnancies. Setting: University hospital. Patient(s): Women with live singleton vaginal deliveries at >24 weeks of gestation. Intervention(s): In vitro fertilization–attained pregnancies (compared with spontaneous ones). Main Outcome Measure(s): Complications of the third stage of labor, defined as manual placental removal (either entire removal due to nonseparation or exploration of the uterine cavity due to suspected retained products of conception). Result(s): Overall, 1,264 IVF pregnancies and 34,166 non-IVF pregnancies were included. Deliveries in the IVF group were characterized by an older maternal age, lower parity, higher rate of diabetes and hypertensive disorders, higher rate of placental abnormalities, earlier gestational age, higher rate of labor induction, chorioamnionitis, and instrumental delivery. Complications of the third stage of labor occurred in 5.9% of IVF deliveries and in 2.8% of controls, and blood transfusion was more prevalent in IVF deliveries. The rate of complications of the third stage were higher in both fresh and frozen transfer cycles as compared with spontaneous pregnancies (5.8%, 8.8%, and 2.8%, respectively), although no difference was noted between fresh and frozen transfers. In vitro fertilization was associated independently with complications of the third stage of labor after adjustment for potential confounders. Conclusion(s): In vitro fertilization is associated independently with an increased risk of complications of the third stage of labor.