Placenta retention is associated with threatened abortion at the early stage of pregnancy

Introduction: Retained placenta (RP) is an obstetric issue complicating around 3% of normal deliveries. Previous studies identified various risk factors for RP. In clinical experience, women with a history of threatened abortion (TA) often are noted to have a higher risk of RP. Yet, limited research has been performed in this area. Aim: To explore the association between RP and TA. Material and methods: A retrospective cohort study including 219 women with viable pregnancies who had TA and 219 women who had not experienced TA with no evidence of subchorionic hematoma (SCH) between January 2019 and January 2021 were included. Demographic information and adverse pregnancy outcomes were compared.