Retained products of conception (RPOC) following delivery without placenta previa: Which patients with RPOC show postpartum hemorrhage?

Introduction: To clarify the perinatal outcome of retained products of conception (RPOC) after 22 weeks or more. Methods: The retrospective cohort study reviewed medical records of patients with RPOC without placenta previa at 186 Japanese perinatal centers. Results: Of the 323 patients with RPOC, pregnancies after assisted reproductive technology (ART) accounted for 43%. Transfusion at delivery was required in 33% of the patients. Logistic regression analyses revealed that transfusion was significantly required in the following situations: ART pregnancy (aOR: 6.0, 95%CI: 2.3-16, P < 0.001), and RPOC length >= 4 cm (aOR: 5.3, 95%CI: 2.1-13, P < 0.001). Transarterial embolization (TAE) and/or hysterectomy for subsequent RPOC-related bleeding was performed in 60 patients with RPOC. Logistic regression analysis revealed that additional interventions were significantly required in the following situations: multiparity (aOR: 6.1, 95%CI: 2.1-17.2, P < 0.001), and hypervascular RPOC (aOR: 12.8, 95%CI: 3.2-51.1, P < 0.001). TAE and/or hysterectomy was also frequently employed in ART pregnancy, although this was not significant (aOR: 2.8, 95%CI: 0.9-8.2, P = 0.063). Discussion: Patients with RPOC were significantly more likely to require transfusion at delivery in the presence of large RPOC and ART. They were also more likely to require hemostatic procedures for subsequent bleeding in the presence of hypervascular RPOC and ART.