About half of all women develop transient urinary incontinence during pregnancy. Three months postpartum, the prevalence and incidence rates of urinary incontinence are 9% to 31% and 7% to 15%, respectively. Antenatal incontinence increases the risk of postpartum incontinence, which in turn increases the risk of long-term persistent incontinence. After the first delivery, women delivered vaginally have two-fold more incontinence than those delivered by cesarean. The protective effect of cesarean on urinary incontinence may dissipate after further deliveries, decreases with age, and is not present in older women. Data are mixed about whether cesarean done before labor confers greater protection than cesarean done after labor. To understand the true impact of cesarean delivery on urinary incontinence, future studies must compare incontinence by planned (not actual) delivery modes, consider a woman's entire reproductive career, focus on leakage severe enough to be problematic, consider other bladder symptoms as well as incontinence, and take into account other risk factors, particularly antepartum urinary incontinence. © 2006 Elsevier Inc. All rights reserved.