Risk of urinary incontinence after childbirth: a 10-year prospective cohort study

OBJECTIVE: To estimate prospectively the effect of first delivery on subjective bladder function and to assess the influence of subsequent deliveries and obstetric events METHODS: We performed a prospective, observational cohort study. During a 10-week period in 1995, 304 of 309 eligible primiparous women (98%) entered the study at the postpartum maternity ward and completed a bladder function questionnaire. The 10-year observational period was completed by 246 of 304 subjects (81%). RESULTS: Prevalence of moderate-severe stress urinary incontinence increased from 5 of 304 subjects (2%) at baseline to 27 of 229 (12%) at 10 years follow-up (P < .001). Prevalence of moderate-severe urinary urgency increased from 0 subjects (0%) at baseline to 31 of 229 (13%) at the 10-year follow-up (P < .001). The relative risk (RR) (adjusted for maternal age and parity) of moderate to severe urinary incontinence increased significantly 10 years after first delivery (RR 5.8, 95% confidence interval CI] 1.2-33.7). At multivariable analysis adjusted for age and parity, stress urinary incontinence symptoms at 9 months and 5 years follow-up were independently associated with the presence of symptoms at 10 years after index delivery (RR 13.3, 95% CI 3.9-33.1 and RR 14.1, 95% CI 2.5-18.8, respectively). Number of vaginal deliveries or other obstetric covariates did not affect the risk of stress urinary incontinence or urinary urgency. CONCLUSION: Vaginal delivery is independently associated with a significant long-term increase in stress urinary incontinence symptoms, as well as urinary urgency, regardless of maternal age or number of deliveries. LEVEL OF EVIDENCE: II-2.