Maternal and fetal morbidity associated with uterine rupture of the unscarred uterus

Objective We sought to report obstetric and neonatal characteristics and outcomes following primary uterine rupture in a large contemporary obstetric cohort and to compare outcomes between those with primary uterine rupture vs those with uterine rupture of a scarred uterus. Study Design This was a retrospective case-control study. Cases were defined as women with uterine rupture of an unscarred uterus. Controls were women with uterine rupture of a scarred uterus. Demographics, labor characteristics, and obstetric, maternal, and neonatal outcomes were compared. Primary rupture case outcomes were also compared by mode of delivery. Results There were 126 controls and 20 primary uterine rupture cases. Primary uterine rupture cases had more previous live births than controls (3.6 vs 1.9; P <.001). Cases were more likely to have received oxytocin augmentation (80% vs 37%; P <.001). Vaginal delivery was more common among cases (45% vs 9%; P <.001). Composite maternal morbidity was higher among primary uterine rupture mothers (65% vs 20%; P <.001). Cases had a higher mean estimated blood loss (2644 vs 981 mL; P <.001) and higher rate of blood transfusion (68% vs 17%; P <.001). Women with primary uterine rupture were more likely to undergo hysterectomy (35% vs 2.4%; P <.001). Rates of major composite adverse neonatal neurologic outcomes including intraventricular hemorrhage, periventricular leukomalacia, seizures, and death were higher in cases (40% vs 12%; P =.001). Primary uterine rupture cases delivering vaginally were more likely to ultimately undergo hysterectomy than those delivering by cesarean (63% vs 9%; P =.017). Conclusion Although rare, primary uterine rupture is particularly morbid. Clinicians must remain vigilant, particularly in the setting of heavy vaginal bleeding and severe pain.