Expectant management of retained products of conception following abortion: A retrospective cohort study

Abstract Objective To clarify the natural history of retained products of conception (RPOC) following abortion at less than 22 weeks of gestation, and those who show major bleeding during course observation. Study design We retrospectively reviewed 640 patients who had spontaneous or artificial abortion at less than 22 weeks of gestation between January 2011 and August 2019 in our institute. Of those, patients with RPOC were included. The maternal background, RPOC characteristics, and subsequent complications including additional interventions were reviewed. Results Fifty-four patients with RPOC were included. The incidence of RPOC was 6.7 %. The median (interquartile range: IQR) RPOC length was 29 (20−38) mm. RPOC hypervascularity was observed in 26 (48 %) patients. The median (IQR) periods of RPOC flow disappearance and RPOC disappearance on ultrasound from abortive treatment were 50 (28−76) and 84 (50−111) days, respectively. Of the 54, 44 patients were selected for expectant management. Of the 44, 34 (77 %) patients were observed without intervention (recovery group); the other 10 (23 %) patients required additional interventions associated with subsequent bleeding (intervention group). Compared with the recovery group, heavy bleeding ( > 500 mL) at abortion (6/10: 60 %) and RPOC hypervascularity (8/10: 80 %) were more frequently observed in the intervention group. Conclusion Expectant management was successful in almost 80 % of patients with RPOC following abortion. The additional interventions were required in patients with heavy bleeding at abortion and RPOC hypervascularity.