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.

Methods: This retrospective cohort study analyzed data from 187 acute-care hospitals across Japan and included patients who experienced uterine rupture. Data were sourced from the Diagnosis Procedure Combination inpatient database, spanning July 2010 to March 2022. The patients' characteristics, in-hospital procedures, and outcomes were compared between those with uterine rupture at  < 37 and  ≥ 37 weeks of gestation. The main outcomes were hysterectomy, complications, proportion of blood transfusions, and postoperative length of stay.

Results: A total of 298 patients were identified, with 161 in the preterm group and 137 in the term group. Placenta accreta spectrum occurred more frequently in the preterm group than in the 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 group. The maternal need for mechanical ventilation (26.3% vs. 12.4%, P = 0.003), the proportion 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. The postoperative hospital stays were also longer in the term group.

Conclusion: This study shows that individual characteristics vary with the gestational age at uterine rupture, and maternal morbidity is notably higher in term compared to preterm ruptures.