Uterine rupture: risk factors and pregnancy outcome.

Objectives: This study aimed at determining risk factors and pregnancy outcome in women with uterine rupture.
Study Design: We conducted a population-based study, comparing all singleton deliveries with and without uterine rupture between 1988 and 1999.
Results: Uterus rupture occurred in 0.035% (n=42) of all deliveries included in the study (n=117,685). Independent risk factors for uterine rupture in a multivariable analysis were as follows: previous cesarean section (odds ratio [OR]=6.0, 95% CI 3.2-11.4), malpresentation (OR=5.4, 95% CI 2.7-10.5), and dystocia during the second stage of labor (OR=13.7, 95% CI 6.4-29.3). Women with uterine rupture had more episodes of postpartum hemorrhage (50.0% vs 0.4%, P<.01), received more packed cell transfusions (54.8% vs 1.5%, P<.01), and required more hysterectomies (26.2% vs 0.04%, P<.01). Newborn infants delivered after uterine rupture were more frequently graded Apgar scores lower than 5 at 5 minutes and had higher rates of perinatal mortality when compared with those without rupture (10.3% vs 0.3%, P<.01; 19.0% vs 1.4%, P<.01, respectively).
Conclusion: Uterine rupture, associated with previous cesarean section, malpresentation, and second-stage dystocia, is a major risk factor for maternal morbidity and neonatal mortality. Thus, a repeated cesarean delivery should be considered among parturients with a previous uterine scar, whose labor failed to progress.