Clinical characteristics and outcomes of preterm versus term uterine rupture: a nationwide observational study

Objective: To assess and compare the clinical aspects of uterine rupture by dividing the gestational age at uterine rupture occurrence into <37-week (preterm) and ≥37-week (term) groups. Design: Retrospective cohort study. Setting: 187 acute-care hospitals in Japan. Population: Pregnant women diagnosed with uterine rupture. Methods: : We conducted a large nationwide study using a national inpatient database from July 2010 to March 2022. The patients’ characteristics, in-hospital procedures, and outcomes were investigated and compared between those who developed uterine rupture at preterm and term groups. Main Outcome Measures: Hysterectomy, complications, proportion of blood transfusions, and postoperative length of stay. Results: : In total, 298 eligible patients were identified (161 in preterm group and 137 in term group). The incidence of placenta accreta spectrum was significantly higher in the preterm than term group (18.0% vs. 6.6%, respectively; P = 0.003). Vacuum delivery (19.0% vs. 0.6%, P < 0.001) and uterine fundal pressure (2.9% vs. 0.0%, P = 0.004) were more likely to be applied in the term than preterm group. The maternal need for mechanical ventilation (26.3% vs. 12.4%, P = 0.003), the incidence of disseminated intravascular coagulation (40.1% vs. 25.5%, P = 0.009), and the requirement for platelet transfusions (32.8% vs. 15.5%, P < 0.001) were greater in the term than preterm group. Additionally, the duration of the postoperative hospital stay was longer in the term group. Conclusions: : This study shows that individual characteristics vary with the gestational age at uterine rupture and that the maternal morbidity rate is notably higher in term than preterm uterine ruptures.