Objective
To compare risk of uterine rupture in women with prior periviable cesarean versus prior term cesarean, independent of initial incision type.
Methods
We conducted a retrospective longitudinal cohort study using Washington State birth certificate data and hospital discharge records, identifying primary cesareans performed at 20-26 weeks and 37-41 weeks of gestation with subsequent delivery between 1989-2008. We compared subsequent uterine rupture risk in the two groups considering both primary incision type and subsequent labor indication and augmentation.
Results
We identified 456 women with index periviable cesarean and 10,505 women with index term cesarean. Women with index periviable cesarean were younger, more frequently of non-white race, more likely to smoke, and more likely to have hypertension. Women in the periviable group had more index classical incisions (42% versus 1%, p<0.001) and fewer subsequent inductions and augmentations (8% vs. 16%, p<0.001). Uterine rupture in the subsequent pregnancy occurred more frequently among women in the index periviable group than those in the index term group (8/456 [1.8%] versus 38/10,505 [0.4%], OR 4.9, 95% CI 2.3-10.6). This relationship persisted among women with a low transverse incision (4/228 [1.8%] versus 36/9,558 [0.4%], OR 4.7, 95% CI1.7 – 13.4).
Conclusion
Cesarean at periviability compared to term is associated with an increased risk for uterine rupture in a subsequent pregnancy, even after low transverse incision. These data support judicious use of cesarean at periviable gestational ages and inform subsequent counseling.