Please cite this paper as: Gartland D, Donath S, MacArthur C, Brown S. The onset, recurrence and associated obstetric risk factors for urinary incontinence in the first 18 months after a first birth: an Australian nulliparous cohort study. BJOG 2012;119:1361–1369.
Objective To investigate the contribution of obstetric risk factors to persistent urinary incontinence (UI) between 4 and 18 months postpartum.
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 of gestation).
Methods Data from hospital records and self-administered questionnaires/telephone interviews at ≤24 and 30–32 weeks of gestation and at 3, 6, 9, 12 and 18 months postpartum analysed using logistic regression.
Main outcome measures Persistent UI 4–18 months postpartum in women continent before pregnancy.
Results Of the women who were continent before pregnancy, 44% reported UI 4–18 months postpartum, and 25% reported persistent UI (symptoms at multiple follow ups). Compared with spontaneous vaginal birth, women who had a caesarean before labour (adjusted odds ratio [aOR] 0.4, 95% confidence interval [95% CI] 0.2–0.9), in first-stage labour (aOR 0.4, 95% CI 0.2–0.6) or in second-stage labour (aOR 0.4, 95% CI 0.2–1.0) were less likely to report persistent UI 4–18 months postpartum. Prolonged second-stage labour in women who had an operative vaginal birth was associated with increased likelihood of UI (aOR 2.5, 95% CI 1.3–4.6). Compared with women who were continent in pregnancy, women reporting UI in pregnancy had a seven-fold increase in odds of persistent UI (aOR 7.4, 95% CI 5.1–10.7).
Conclusions Persistent UI is common after childbirth and is more likely following prolonged labour in combination with operative vaginal birth. The majority of women reporting persistent UI at 4–18 months postpartum also experienced symptoms in pregnancy.