Incidence and risk factors of bladder injury during cesarean delivery: a cohort study.

Purpose: To identify risk factors associated with bladder injury during cesarean delivery, and to determine the frequency of associated morbidities.

Methods: Data obtained from the United States' Health Care Cost and Utilization Project-Nationwide Inpatient Sample were used to conduct a retrospective population-wide cohort study. ICD-9 codes were used to identify women who underwent a cesarean delivery between 1999 and 2015. Subsequently, women were classified based on whether or not they experienced a bladder injury during delivery. Multivariate logistic regression was used to determine predictors of bladder injury in cesarean deliveries and to examine the associated morbidities while adjusting for baseline maternal demographics and clinical characteristics.

Results: Of 4,169,681 cesarean deliveries identified, there were 7,627 (0.2%) bladder injuries for an overall incidence of 18 per 10,000. Women ≥ 35 years were at greater risk of bladder injury 1.5 (1.4-1.6), as were women with endometriosis 2.0 (1.5-2.7) and Crohn's disease 2.7 (1.7-4.2). Risk of bladder injury increased if the cesarean delivery was associated with placenta previa 2.2 (1.9-2.4), previous cesarean delivery 4.3 (4.1-4.6), failed instrumental delivery 4.1 (3.5-4.8), fetal distress 1.7 (1.6-1.8), failed trial of labor after cesarean delivery 1.3 (1.2-1.4), and labor dystocia 1.7 (1.6-1.8). Cesarean hysterectomies presented the greatest risk for bladder injury 37.0 (33.7-40.6). Bladder injury was associated with an increased frequency of sepsis, venous thromboembolism, peritonitis, blood transfusions and longer hospital stays.

Conclusion: Bladder injury during cesarean deliveries is a rare outcome but it is more common among women with certain demographic and clinical characteristics. Among these cases, strategies to prevent sepsis and venous thromboembolism should be considered.