Objective: To estimate the rate of and risk factors for bladder injury in vaginal birth after cesarean (VBAC) candidates.
Methods: Between 1995 and 2000, a 17-center, retrospective cohort study was performed, evaluating women with prior cesarean delivery for delivery mode-specific morbidity during subsequent pregnancy. Trained nurses extracted information from medical records on demographics, medical and obstetric history, pregnancy, and delivery. This secondary analysis examines the rate and risk factors for bladder injury, defined as having occurred if identified and recorded by the physician at delivery. Univariable and multivariable analyses were performed.
Results: Of 25,005 patients with at least one prior cesarean delivery, 107 (0.43%) sustained a bladder injury, and 91.6% (n=98) of these occurred without concurrent uterine rupture. Bladder injury risk was not affected by delivery mode: VBAC trial compared with elective cesarean delivery (0.44% compared with 0.42%, adjusted odds ratio [OR] 1.36, 95% confidence interval [CI] 0.85-2.19). For the women who undertook a VBAC trial and did not experience a uterine rupture, failure to deliver vaginally was the only predictor of bladder injury (0.86% compared with 0.22%, adjusted OR 4.61, 95% CI 2.70-8.11). In women who elect repeat cesarean delivery, greater than one prior cesarean delivery was significantly associated with bladder injury (0.68% compared with 0.29%, adjusted OR 2.40, 95% CI 1.30-4.43).
Conclusion: Risk of bladder injury in women with a prior cesarean delivery is not affected by planned mode of delivery. Although rare, bladder injury in women undergoing VBAC is strongly associated with a failed VBAC trial. A heightened awareness for bladder injury is warranted when performing repeat cesarean deliveries in the setting of failed VBAC attempts.
Level of evidence: II.