Background: Our aim was to estimate the prevalence of stress urinary incontinence 4 years after the first delivery and analyze its risk factors., Methods: A retrospective cohort survey was conducted in a French university hospital. The 669 primiparous women who delivered in our department in 1996 a singleton in a vertex position between 37 and 41 weeks of amenorrhea were included. A mailed questionnaire was sent 4 years after the indexed delivery. The main outcome measure was stress urinary incontinence 4 years after the first delivery., Results: Three hundred and seven women replied, 274 had moved and 88 did not respond. Four years after the first delivery, prevalence of stress urinary incontinence was 29% (89/307). According to multiple logistic regression analysis, the independent risk factors were urine leakage before the first pregnancy [odds ratio (OR) 18.7; 95% confidence interval (CI) 3.6-96.4], urine leakage during the first pregnancy (OR 2.5; 95% CI 1.3-4.8), duration of first labor > or = 8 h (OR 3.1; 95% CI 1.7-5.7), mother's age > 30 years at the first delivery (OR 2.4; 95% CI 1.4-4.2) and cesarean section at the first delivery (OR 0.3; 95% CI 0.1-0.9)., Conclusion: Our results suggest that stress urinary incontinence after pregnancy arises from a multifactorial condition. The main risk factors are: age, previous incontinence (before or during the first pregnancy), prolonged labor and vaginal delivery.