The RPOC long axis is a simple indicator for predicting the need of invasive strategies for secondary postpartum hemorrhage in either post-abortion or post-partum women: a retrospective case control study

BACKGROUND: The retained products of conception (RPOC) and related conditions (RPOC-ARC) are the main cause of secondary postpartum hemorrhage (sPPH), but there is no clear consensus for their management. The purpose of this study was to characterize those RPOC-ARC that require invasive treatment and those that could be managed more conservatively. METHODS: We retrospectively analyzed 96 cases of RPOC-ARC that occurred after miscarriage, abortion, or delivery at a gestational age between 12 and 42 completed weeks, that were managed within our institution from May 2015 to August 2020. We reviewed the associations between the occurrence of sPPH requiring invasive treatment with clinical factors such as the maternal background and the characteristics of the lesions. RESULTS: The range of gestational age at delivery in our study was 12–21 weeks in 61 cases, 22–36 in 5, and 37 or later in 30. Among them, nine cases required invasive procedures for treatment. The onset of sPPH was within one month of delivery in all but two cases, with a median of 24 days (range 9–47). We found significant differences between requirements for invasive versus non-invasive strategies according to gestational age at delivery, assisted reproductive technology (ART) pregnancy, amount of blood loss at delivery, and the long axis of the RPOC-ARC lesion (p = 0.028, p = 0.009, p = 0.004, and p = 0.002, respectively). Multivariate analysis showed that only the long axis of the lesion showed a significant difference (p = 0.029). The Receiver Operating Characteristic (ROC) curve for predicting the need for invasive strategies using the long axis of the lesion showed that with a cutoff of 4.4 cm, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) was 87.5, 90.0, 43.8, and 98.7%, respectively. CONCLUSION: The long axis of the RPOC-ARC is a simple indicator for predicting which sPPH will require invasive procedures, which use is rare in cases with lesions less than 4.4 cm or those occurring after the first postpartum month. Conservative management should be considered in such cases.