Obstetric practice and the prevalence of urinary incontinence three months after delivery

Objective To examine the relation between obstetric factors and the prevalence of urinary incontinence three months after delivery. Design 2134 postal questionnaires sent between August 1989 and June 1991. Setting Teaching hospital in Dunedin, New Zealand. Subjects All women three months postpartum who were resident in the Dunedin area. Main outcome measure Prevalence of urinary incontinence. Results 1505 questionnaires were returned (70.5% response rate). At three months postpartum 34.3 % of women admitted to some degree of urinary incontinence with 3.3 % having daily or more frequent leakage. There was a significant reduction in the prevalence of incontinence for women having a caesarean section, in particular in primiparous women with a history of no previous incontinence (prevalence of incontinence following a vaginal delivery 24.5%, following a caesarean section 5.2% P = 0.002). There was little difference between elective caesarean sections and those carried out in the first and second stages of labour. The odds ratios for women having a caesarean section were 0.4 (95 % confidence interval (CI) 0.2-0.7) (all women and all primiparae) and 0.2 (95% CI 0.0-0.6) (primipara with no previous incontinence) in comparison with those having a normal vaginal delivery. The prevalence of incontinence was also significantly lower in women having had two caesarean sections (23.3 %; P = 0.05) but similar in those women having three or more caesarean sections (38.9 %) in comparison with those women who delivered vaginally (37.7 %). Other significant independent odds ratios were found for daily antenatal pelvic floor exercises (PFE) (0.6, 95 % CI 0.4-0.9), parity greater than or equal to 5 (2.2, 95% CI 1.0-4.9) and pre-pregnancy body mass index (1.07, 95% CI 1.04-1.10). Conclusions Adverse risk factors for urinary incontinence at three months postpartum are vaginal delivery, obesity and multiparity (greater than or equal to 5). Caesarean section and daily antenatal PFE appear to be protective, although not completely so.