Complications Following Late Second-Trimester Dilatation and Evacuation: A Retrospective Cohort Comparison of Missed and Induced Abortions

Objective: Second-trimester D&E is generally safe, but whether pregnancy viability (missed vs induced abortion) alters complication risk remains unclear as comparative data remain limited. We compared complication rates following second-trimester dilatation and evacuation (D&E) for missed abortion (MA) versus induced abortion (IA) and assess potential contributing factors to increased morbidity in MA cases. Methods: This retrospective cohort study included all consecutive second-trimester (13– 20 weeks) D&E procedures performed for MA and IA at a single tertiary medical center between 2002 and 2023. Patients were divided into two groups based on fetal viability at the time of the procedure. Data were extracted from electronic medical records and validated by trained clinical research associates. The primary outcome was maternal complications, including hemorrhage, uterine atony, disseminated intravascular coagulation (DIC), infection, cervical or vaginal lacerations, uterine perforation, hysterectomy, and bladder or ureteral injury. Results: A total of 974 women underwent second-trimester D&E, including 202 (20.7%) in the MA group and 772 (79.3%) in the IA group. Women in the MA group were significantly older (32.1± 6.1 vs 29.1± 7.2 years, p < 0.01) and had higher parity (1.54± 1.46 vs 1.12± 1.32, p < 0.01). Compared to IA, MA was associated with a significantly higher incidence of hemorrhage (10.4% vs 1.3%, p < 0.01), blood transfusions (7.4% vs 0.9%, p < 0.01), DIC (0% vs 1.5%, p=0.007), and uterine atony (2.5% vs 0.1%, p < 0.01). Missed abortion was independently associated with complications (aOR 5.70, 95% CI 3.02– 10.74, p < 0.01). Notably, cervical preparation was required in only 19% of MA cases compared to 79% of IA cases (p < 0.01). Conclusion: MA is associated with an increased risk of hemorrhagic and infectious complications following second-trimester D&E compared to IA. Differences in inflammatory response, coagulation status, and cervical preparation protocols may contribute. These findings highlight the need for risk stratification, pre-procedural cervical preparation, and closer post-procedural monitoring for patients undergoing D&E for MA. Plain Language Summary: A retrospective study revealed a significantly higher incidence of hemorrhagic complications, uterine atony, and blood transfusion, in patients undergoing Dilation and Evacuation (D&E) for missed abortion over induced abortion. This emphasizes the need for perioperative strategies and individualized patient management. Keywords: missed abortion, induced abortion, dilatation and evacuation, second-trimester abortion, complications, hemorrhage