Manual removal of the placenta and postpartum hemorrhage: A multicenter retrospective study.

AIM In postpartum women, retained placenta is diagnosed in the absence of signs of placental separation and expulsion, and requires manual removal of the placenta (MROP). MROP may lead to massive hemorrhage, hemodynamic instability, and the need for emergency interventions including blood transfusion, interventional radiology, and hysterectomy. In this study, we aimed to identify the risk factors for retained placenta requiring MROP after vaginal delivery and postpartum hemorrhage (PPH) following MROP. METHODS A multicenter retrospective study was performed using data from women who delivered at term between 2010 and 2018 at 13 facilities in Japan. Of 36 454 eligible women, 112 women who required MROP were identified. Multivariate logistic regression analyses were conducted to evaluate the risk factors for retained placenta and PPH following MROP. RESULTS A history of abortion, assisted reproductive technology (ART), instrumental delivery, and delivery of small-for-gestational-age infant were independent risk factors for MROP (adjusted odds ratios [95% confidence intervals]: 1.93 [1.28-2.92], 8.41 [5.43-13.05], 1.80 [1.14-2.82], and 4.32 [1.97-9.48], respectively). ART was identified as an independent risk factor for PPH (adjusted odds ratio [95% confidence interval]: 6.67 [2.42-18.36]) in patients who underwent MROP. CONCLUSION ART pregnancies significantly increased the risk of retained placenta requiring MROP and PPH. Our results suggest that clinicians need consider patient transfer to a higher-level facility and preparation of sufficient blood products before initiating MROP in cases of ART pregnancies. Our study may assist in identifying high-risk women for PPH before MROP and in guiding treatment decisions, especially in facilities without a blood bank.