A comparison of the long-term consequences of vaginal delivery versus caesarean section on the prevalence, severity and bothersomeness of urinary incontinence subtypes: a national cohort study in primiparous women

Objective: To study the effect of one vaginal delivery (VD) compared with one caesarean section (CS) on the prevalence, severity and bothersomeness of urinary incontinence (UI) subtypes--stress (SUI), urge (UUI) and mixed (MUI)--20 years after delivery.

Design: Registry-based national cohort study.

Setting: Women who returned postal questionnaires (response rate 65.2%) in 2008.

Population: Primiparae with one birth in 1985-88 (n = 5236) and no further births.

Methods: Medical Birth Register data were linked to a questionnaire. Analysis of variance and multivariate analysis were used to obtain adjusted prevalences and odds ratios (adjOR).

Main outcome measures: Prevalence, risk factors, severity, bothersomeness of UI subtypes.

Results: The prevalence of SUI, UUI and MUI was 15.3, 6.1, 14.4%, respectively, and was higher for all subtypes after VD versus CS. Moderate to severe incontinence was more prevalent after VD (21.3%) compared with CS (13.5%; adjOR 1.68, 95% confidence interval [95% CI] 1.40-2.03). Bothersome incontinence differed between MUI (38.9%), UUI (27.1%) and SUI (18.0%). The prevalence of bothersome UI was higher after VD compared with CS (11.2 versus 6.3%; adjOR 1.85, 95% CI 1.42-2.39) and consulting a doctor for UI was reported more often after VD than CS. Bothersome MUI occurred in 40.0% of incontinent women after VD compared with 29.9% after CS (adjOR 1.65, 95% CI 1.07-2.54). Symptomatic pelvic organ prolapse was an important modifier of UI with regard to its prevalence, duration, type and bothersomeness.

Conclusion: The prevalence of SUI, UUI and MUI was higher and moderate to severe UI and bothersome UI were reported more often after VD than CS 20 years after one delivery.