Vaginal Birth Linked to Higher Risk of Midlife Urinary Incontinence: SWAN Cohort Study
Canada: A recent longitudinal analysis based on the Study of Women's Health Across the Nation (SWAN) cohort has shed light on how childbirth experiences-particularly the number of children a woman has and the mode of delivery-can influence the risk of urinary incontinence (UI) during midlife.
The analysis showed that vaginal births significantly raised the risk of stress (OR 2.11) and mixed urinary incontinence (OR 1.89) in midlife compared to cesarean deliveries. Women with both vaginal and cesarean births had even higher odds of mixed incontinence (OR 2.17). In contrast, urge incontinence was more closely linked to aging than childbirth.
The findings were published online in Scientific Reports on 07 April 2025.
Parity has been shown to increase the risk of urinary incontinence, but the extent of this risk appears to vary based on the mode of delivery. To explore this relationship further, Nikki L Stephenson, Department of Obstetrics & Gynecology, University of Calgary, Calgary, AB, Canada, and colleagues examined how different delivery methods—vaginal versus cesarean—were associated with the prevalence of urge, stress, and mixed urinary incontinence during midlife.
For this purpose, the researchers examined the association between mode of delivery and subtypes of urinary incontinence using data from the SWAN cohort. They compared women who had undergone vaginal, cesarean, or a combination of both delivery types with those who had never given birth, aiming to understand how different childbirth experiences influence the risk of urge, stress, and mixed incontinence in midlife.
The key findings of the study were as follows:
- Women who delivered vaginally had a significantly higher prevalence of all types of urinary incontinence compared to those who were nulliparous or delivered via other modes.
- No significant differences in urinary incontinence were observed when comparing parous women (regardless of delivery type) with nulliparous women overall.
- Compared to cesarean deliveries, vaginal births were associated with significantly higher odds of stress urinary incontinence in midlife.
- Women who had both vaginal and cesarean deliveries faced significantly increased odds of developing mixed urinary incontinence compared to those who delivered exclusively via cesarean section.
- Urge urinary incontinence was more strongly linked to aging rather than childbirth history.
- Vaginal deliveries raised the risk of both stress and mixed urinary incontinence in midlife compared to cesarean births.
- A combination of vaginal and cesarean deliveries further elevated the risk of mixed urinary incontinence during middle age.
“Parity and mode of delivery emerge as key factors influencing urinary incontinence in midlife. Parous women face a higher risk of stress and mixed incontinence, while the likelihood of urge incontinence appears lower compared to nulliparous women,” the authors noted. They further observed that “among multiparous women, vaginal delivery is associated with a greater risk of stress and mixed incontinence than cesarean birth.”
“These findings highlight the need for further research to validate the results across diverse populations and to better understand the underlying mechanisms driving these associations,” they concluded.
Reference:
Stephenson, N. L., Brenner, D., Brennand, E., Robert, M., Prisnie, K., & Metcalfe, A. (2025). Longitudinal analysis of the association between parity, mode of delivery and urinary incontinence in midlife using the SWAN cohort data. Scientific Reports, 15(1), 1-8. https://doi.org/10.1038/s41598-025-85603-0
