To investigate the spontaneous outcomes of vascularized retained products of conception (RPOC) detected by ultrasonography after second-trimester abortion, and to identify the predictive factors for the development of severe postpartum hemorrhage (SPPH).This is a retrospective cohort study on all cases after second-trimester abortion managed at our institute between January 2014 and December 2016. We assessed the associations between the occurrence of SPPH requiring invasive treatment and clinical factors including ultrasonographic findings (size and the vascularity status of RPOC classified as follows: type 1: vascularity confined to endometrium, type 2: vascularity reaching <1/2 myometrium, and type 3: vascularity reaching ≥1/2 myometrium) in vascularized RPOC cases.Among 103 cases after second-trimester abortion, 19 patients (18.4%) were diagnosed as RPOC, and five patients eventually failed expectant management due to SPPH. Of them, 66.7% (4/6) of patients with type 3 developed SPPH as compared with 7.7% (1/13) of patients with type 1/type 2 (p < .05). The maximum vascularized mass diameter was significantly greater among the five patients who experienced SPPH than among the 14 patients who demonstrated spontaneous remission (43.0 ± 12.0 mm versus 20.7 ± 8.3 mm, p < .01). Patients with type 3 RPOC and a maximum vascularized mass diameter ≥30 mm, compared with other patients, demonstrated sensitivity, specificity, and risk ratio related to SPPH of 80, 92.9%, and 11.2, respectively.Our findings suggest that the ultrasonographic assessment of RPOC focused on the depth of vascularity in combination with the measurement of its size appears to be essential in determining women with RPOC who are at high risk for SPPH.
