Abstract Introduction  Few studies have examined associations of prepregnancy urinary incontinence (UI). Methods  Multicentre prospective pregnancy cohort study (nâ=â1,507) using standardised measures to assess frequency and severity of UI. Results  Prevalence of UI increased from 10.8% in the 12 months before the index pregnancy to 55.9% in the third trimester. Stress incontinence (36.9%) and mixed incontinence (13.1%) were more common during pregnancy than urge incontinence alone (5.9%). UI before pregnancy was associated with childhood enuresis (adjusted odds ratio (AdjOR)â=â2.4, 95% confidence interval (CI) 1.6â3.4), higher maternal body mass index (AdjORâ=â2.3, 95% CI 1.4â3.8), and previous miscarriages or terminations (AdjORâ=â1.6, 95% CI 1.1â2.3). The strongest predictor of incident UI in pregnancy was occasional leakage (less than once a month) before pregnancy (AdjORâ=â3.6, 95% CI 2.8â4.7). Conclusions  Further research is needed to elucidate the complex interplay of prepregnancy and pregnancy-related factors in the aetiology of UI in nulliparous women. [ABSTRACT FROM AUTHOR]