Effects of prolonged second stage, method of birth, timing of caesarean section and other obstetric risk factors on postnatal urinary incontinence: an Australian nulliparous cohort study

Objective To investigate the contribution of prolonged labour, method of birth, timing of caesarean section and other obstetric risk factors to postpartum urinary incontinence. Design Prospective pregnancy cohort. Setting Six metropolitan public hospitals in Victoria, Australia. Sample A total of 1507 nulliparous women recruited to the maternal health study in early pregnancy (<= 24 weeks). Method Data from hospital medical records and self-administered questionnaires/telephone interviews at <= 24 and 30-32 weeks of gestation and 3 months postpartum analysed using univariable and multivariable logistic regression. Main outcome measure Urinary incontinence 3 months postpartum in women continent before the index pregnancy. Results Of the women continent before pregnancy, 26% reported new incontinence at 3 months postpartum. Compared with women who had a spontaneous vaginal birth, women who had a caesarean section before labour (adjusted odds ratio [OR] 0.2, 95% CI 0.1-0.5) or in the first stage of labour (adjusted OR 0.2, 95% CI 0.1-0.4) were less likely to be incontinent 3 months postpartum. Adjusted OR for incontinence after caesarean section in the second stage of labour compared with spontaneous vaginal birth was 0.5 (95% CI 0.2-1.0). Prolonged second stage labour was associated with increased likelihood of postpartum incontinence in women who had a spontaneous vaginal birth (adjusted OR 1.9, 95% CI 1.1-3.4) or operative vaginal birth (adjusted OR 1.7, 95% CI 1.0-2.8). Conclusions In addition to pregnancy itself, physiological changes associated with the second stage of labour appear to play a role in postpartum urinary incontinence.