Women Over 30 Face Greater Bladder Risks from Early Pelvic Floor Changes After Delivery: Study Finds

Women with an enlarged genital hiatus (GH) or pelvic organ prolapse (POP) were at notably higher risk of OAB by 50% and 80%, respectively. The association was even more pronounced in women over the age of 30, with adjusted relative risks rising to 2.1 for GH and 2.2 for POP. These findings suggest that anatomical alterations in the pelvic floor soon after childbirth may be key contributors to the onset of OAB, particularly in older postpartum women.

Genital hiatus enlargement has been previously linked to POP and OAB several years after childbirth, typically within a 5–to 10-year timeframe. However, it remains unclear whether this association appears earlier in the postpartum period. To address this gap, Whitney K. Hendrickson, Division of Urogynecology, Department of Obstetrics and Gynecology, University of Utah Health Sciences, Salt Lake City, UT, and colleagues aimed to evaluate the relationship between the development of OAB within one year after the first vaginal delivery and three key factors: enlarged GH, anatomic POP, and self-reported bulge symptoms.

For this purpose, the researchers conducted a secondary analysis of a prospective cohort involving primiparous women with singleton-term vaginal deliveries. Participants completed physical exams and symptom questionnaires during the third trimester, at 8 weeks, and 1 year postpartum.

Overactive bladder was defined as urinary urgency along with either frequency, nocturia, or urgency incontinence, based on the Epidemiology of Prolapse and Incontinence Questionnaire. An enlarged genital hiatus was defined as >4 cm, and anatomic pelvic organ prolapse (POP) as vaginal descent to or beyond the hymen. The researchers used Poisson regression to assess associations between OAB and GH or POP at 1 year postpartum.

Key Findings:

• The study included 579 participants with a mean age of 29 of whom 17% identified as Hispanic.
• At one year postpartum, both enlarged genital hiatus and anatomic pelvic organ prolapse were independently associated with a higher prevalence of overactive bladder (OAB).
• Women with an enlarged genital hiatus had a 50% increased risk of developing OAB (adjusted risk ratio [aRR] 1.5).
• Those with pelvic organ prolapse faced an 80% higher risk (aRR 1.8).
• The associations were more pronounced in women over 30 years of age, with genital hiatus linked to a more than twofold increased risk of OAB (aRR 2.1) and pelvic organ prolapse associated with a similar elevated risk (aRR 2.2).
• No significant association was observed in women under the age of 30.

The study concludes that an enlarged genital hiatus and pelvic organ prolapse are linked to a higher risk of overactive bladder as early as one year after vaginal delivery, especially in women over 30. These findings suggest that genital hiatus could serve as an early indicator of pelvic floor dysfunction, helping to identify women at greater risk for OAB and prolapse postpartum.

Reference:

Hendrickson, W. K., Allshouse, A., Nygaard, I. E., & Swenson, C. W. (2025). ASSOCIATION BETWEEN ENLARGED GENITAL HIATUS AND PROLAPSE WITH OVERACTIVE BLADDER 1 YEAR AFTER VAGINAL DELIVERY. American Journal of Obstetrics and Gynecology. https://doi.org/10.1016/j.ajog.2025.04.019