Immediate initiation of oral contraceptive pills after an early pregnancy loss does not increase the risk of retained products of conception.

Introduction: Retained products of conception (rPOC) are a common complication following early pregnancy loss (EPL) and may contribute to infertility and delays in subsequent fertility treatment. Oral contraceptive pills (OCPs) are frequently initiated after EPL in infertility patients to synchronize the menstrual cycle prior to fertility treatment; however, it is unknown whether immediate initiation of OCPs affects the incidence of rPOC. Methods: We conducted a retrospective cohort study at a single academic reproductive endocrinology and infertility practice including patients who experienced EPL following embryo transfer between 2015 and 2023 and subsequently underwent office hysteroscopy (OHS). Patient demographics, infertility diagnoses, EPL management modality, and OCP initiation following resolution of EPL were collected through chart review. rPOC was diagnosed by direct visualization during OHS. Results: A total of 188 women with EPL following embryo transfer were included, of whom 42 (22.3%) were diagnosed with rPOC at the time of OHS. There were no significant differences in demographic or infertility characteristics between patients with and without rPOC. Following EPL, 52.1% of patients underwent surgical management, 31.9% expectant management, and 16.0% medical management, with no significant association between management modality and rPOC ( Discussion: Immediate initiation of OCPs following EPL after embryo transfer was not associated with an increased risk of rPOC in this infertility population. These findings support the use of OCPs after EPL to facilitate fertility treatment planning, though larger prospective studies are needed to further evaluate factors associated with rPOC.