Risk of Pelvic Floor Disorders Varied by Child Delivery Mode

The risk of pelvic floor disorders for women years after childbirth varied depending on mode of delivery, researchers found.

Women with cesarean delivery had a lower hazard of stress urinary incontinence, overactive bladder, and pelvic organ prolapses compared with women with spontaneous vaginal deliveries, reported Joan L. Blomquist, MD, of Greater Baltimore Medical Center in Maryland, and colleagues.

By contrast, women with operative vaginal delivery were associated with a higher hazard of anal incontinence and pelvic organ prolapse, they wrote in JAMA.

They noted that prior research found that about a quarter of U.S. women in 2005 to 2006 had one or more pelvic floor disorders, with the rate more than doubling for women ages ≥80.

But “the biological mechanisms underlying pelvic floor disorders remain uncertain,” though epidemiologic studies have suggested it may be associated with childbirth, the authors added.

“Little is known, however, about the association of various obstetrical exposures with the course and progression of pelvic floor disorders during a woman’s life,” they wrote.

Researchers examined data from the Mother’s Outcomes After Delivery study, a longitudinal cohort study of parous women, where authors said that participants were recruited from a community hospital 5 to 10 years after their first delivery and followed annually for up to 9 years.

Women were examined by mode of delivery: C-section, spontaneous vaginal birth (≥1 spontaneous vaginal delivery and no operative vaginal deliveries), or operative vaginal birth.

Four pelvic floor disorders were assessed annually via the Epidemiology of Prolapse and Incontinence Questionnaire (EPIQ), as well as a physical examination, the authors said. They included:

• Stress urinary incontinence
• Overactive bladder
• Anal incontinence
• Pelvic organ prolapse

Overall, data was examined from 1,528 study participants — 778 women in the C-section birth group, 565 women in the vaginal birth group, and 185 in the operative vaginal birth group. Median age at first delivery was about 30, while median age at enrollment was about 38. There were 28% of women with one delivery, 56% with two, and 16% with three or more deliveries. In addition, 72% of women were multiparous at enrollment.

They found that during a median follow-up of about 5 years, there were 138 cases of stress urinary incontinence, 117 cases of overactive bladder, 168 cases of anal incontinence, and 153 cases of pelvic organ prolapse.

But these varied depending on mode of delivery. The authors found that compared with spontaneous vaginal delivery, C-section delivery was associated with significantly lower hazard of stress urinary incontinence (adjusted HR 0.46, 95% CI 0.32-0.67), overactive bladder (adjusted HR 0.51, 95% CI 0.34-0.76), and pelvic organ prolapse (adjusted HR 0.28, 95% CI 0.19-0.42).

However, operative vaginal delivery was associated with a significantly higher hazard of anal incontinence (adjusted HR 1.75, 95% CI 1.14-2.68) and pelvic organ prolapse (adjusted HR 1.88, 95% CI 1.28-2.78). The authors also found that “the association with delivery mode was the most pronounced for [pelvic organ prolapse].”

When discussing how this study provided “a more complete picture” of the incidence of these examined pelvic floor disorders over time, the authors noted that “[pelvic organ prolapse]… had a longer latency after childbirth than [stress urinary incontinence] and [anal incontinence].”

They stated that such “temporal differences” could explain the different patterns seen in surgery for pelvic organ prolapse and stress urinary incontinence.

Study limitations included potential misclassification of pelvic floor disorders, as well as use of “dichotomous definitions” of pelvic floor disorders, as the authors noted that “worsening of a mild pelvic floor disorder over time may also be clinically relevant.” They also said that while this may be the longest cohort study on the epidemiology of pelvic floor disorders to date, “the duration of follow-up was not adequate to look at patterns of hazard in older women.”