(739) Risk factors associated with uterine rupture in stillbirth pregnancies with prior cesarean

Case-control study using US vital statistics fetal death data from all stillbirths in the US, 2005-2021. Study population was limited to patients with prior cesarean and birth at ≥ 20 weeks gestation. The case and controls were deliveries with and without uterine rupture, respectively. Logistic regression estimated the risk of various factors and uterine rupture while adjusting for coexisting risks.

Results:

There were 422,963 stillbirths during the study period. 15,132(3.6%) were ≥ 20wks and had prior cesarean. 332 (2.2%) cases had uterine rupture and 14,800 (97.8%) controls did not. Hispanic ethnicity was associated with lower odds of rupture, whereas no prenatal care, two or more prior cesareans, preterm delivery < 28 weeks, and TOLAC were associated with higher odds of rupture, even after adjusted analyses. The most significant association was trial of labor after cesarean (TOLAC) being nearly 4.5 times more likely to result in uterine rupture (OR=4.48 [3.28-6.13], p< 0.001). The rate of uterine rupture among those undergoing TOLAC with 1, 2 and 3 or greater cesareans was 8.9%, 22.9%, and 19.7%, respectively.

Conclusion:

Sociodemographic, medical, and obstetric factors influence the risk of uterine rupture among pregnancies complicated by stillbirth and prior cesarean. The highest risk for uterine rupture was observed with no prenatal care, early preterm delivery, higher number of prior cesareans and TOLAC attempt. These data may be useful in counseling regarding mode of delivery and anticipated risks when managing delivery in cases of stillbirth.