ObjectiveTo assess specific parturition and reproductive variables as potential risk factors for urinary incontinence in later life.Methodsa mail survey was conducted with a random sample of 1922 women members of a large health maintenance organization. Multivariate analysis was used to estimate the independent association between parturition factors, husterectomy, hormone use, and incontinence.ResultsCompleted surveys were returned by 939 women (49%), 682 of whom reported at least one episode of incontinence in the past 12 months or ever having been treated for incontinence. On univariate analysis, women with incontinence were more likely to be white and heavier and to have had a hysterectomy before age 45, at least one live birth, a postdate (at least 42 weeks' gestation) birth, alabor lasting longer than 24 hours, and exposure to oxytocin. The risk of incontinence increased significantly with the number of exposures to oxytocin. In a multivariate model including age, there was a significant association between incontinence and white race (odds ratio [OR] 1.8, 95% confidence interval [CI] 1.2, 2.8), body mass (OR for fourth quartile 3.0, 95% CI 1.8, 5.0), estrogen replacement (OR 1.9, 95% CI 1.3, 2.8) and oxytocin (OR 1.9, 95% CI 1.0, 3.6). Parity was also associated with incontinence (P< .05).ConclusionThis study supports previous findings of a positive association between urinary incontinence and body mass, parity, and use of estrogen. In addition, we found a significant independent association between exposure to oxytocin during labor and incontinence in later life.