Longitudinal changes in overactive bladder and stress incontinence among parous women.

AIMS: To describe longitudinal changes in symptoms of overactive bladder (OAB) and stress urinary incontinence (SUI) among parous women.

METHODS: At annual examinations, beginning at least 5 years from first delivery, OAB and SUI were assessed using the Epidemiology of Prolapse and Incontinence Questionnaire. Published thresholds were used to define "bothersome" symptom scores. The prevalence, the incidence of bothersome symptoms, and treatment rates were calculated. In separate analyses for women who delivered by cesarean versus vaginal delivery, odds of SUI or OAB symptoms (score > 0) were modeled as a function of time since childbirth, age, race, and obesity. Among those with persistent symptoms, severity symptom score was modeled as a function of time since childbirth and these same covariates.

RESULTS: One thousand four hundred and eighty-one participants completed up to 5 annual assessments (2,722 woman-years). During follow-up, the incidences of bothersome SUI and OAB were 2.5/100 woman-years and 1.7/100 woman-years, respectively. Although SUI and OAB symptoms were more common in the vaginal birth group (P < 0.001), the odds of symptoms increased since increasing time from delivery in the cesarean group. Symptom severity did not change substantially over time in either group. Obesity was strongly associated with symptoms related to SUI and OAB.

CONCLUSIONS: Five years from first delivery, symptoms related to SUI and OAB were more common and of greater severity after vaginal than cesarean birth. However, differences between these two groups lessen as time from childbirth increases. Obesity control should be a primary target for reduction of incontinence and incontinence severity among parous women.