Blomquist JL, et al. - In this cohort study of 1528 women, researchers described the incidence of pelvic floor disorders (eg, urinary incontinence), which affect approximately 25% of women in the US, after childbirth and identified maternal and obstetrical characteristics related to patterns of incidence 1 to 2 decades after delivery. Findings suggested an association of cesarean delivery with significantly lower hazard for stress urinary incontinence, overactive bladder, and pelvic organ prolapse vs spontaneous vaginal delivery. On the other hand, operative vaginal delivery was linked to the significantly higher hazard of anal incontinence and pelvic organ prolapse. An association was found between a larger genital hiatus and increased risk of pelvic organ prolapse regardless of the mode of delivery.

Methods

• For this cohort study, women were recruited from a community hospital 5 to 10 years after their first delivery and followed up annually for up to 9 years.
• Recruitment was based on delivery methods; delivery groups were matched for age and years after first delivery.
• Of the 4072 women who were eligible, 1528 were registered between October 2008 and December 2013.
• Through April 2017, annual follow-up continued.
• Participants were categorized as follows: cesarean birth (cesarean deliveries only), spontaneous vaginal birth (≥1 spontaneous vaginal delivery and no operative vaginal deliveries), or operative vaginal birth (≥1 operative vaginal delivery).
• Main outcomes and measures included stress urinary incontinence (SUI), overactive bladder (OAB), and anal incontinence (AI), defined using validated threshold scores from the Epidemiology of Prolapse and Incontinence Questionnaire, and pelvic organ prolapse (POP), measured using the Pelvic Organ Prolapse Quantification Examination.
• Using parametric methods, cumulative incidences by delivery group were estimated.
• Using semiparametric models, hazard ratios by exposure were estimated.

Results

• Of the 1528 women (778 in the cesarean birth group, 565 in the spontaneous vaginal birth group, and 185 in the operative vaginal birth group), the median age at first delivery was 30.6 years, 1092 women (72%) were multiparous at enrollment (2887 total deliveries), and the median age at registration was 38.3 years.
• There were 138 cases of SUI, 117 cases of OAB, 168 cases of AI, and 153 cases of POP during a median follow-up of 5.1 years (7804 person-visits).
• The 15-year cumulative incidences of pelvic floor disorders after first delivery were as follows: SUI, 34.3% (95% CI, 29.9%-38.6%); OAB, 21.8% (95% CI, 17.8%-25.7%); AI, 30.6% (95% CI, 26.4%-34.9%), and POP, 30.0% (95% CI, 25.1%-34.9%) for spontaneous vaginal delivery (reference).
• Cesarean delivery was correlated with significantly lower hazard of SUI (adjusted hazard ratio [aHR], 0.46 [95% CI, 0.32-0.67]), OAB (aHR, 0.51 [95% CI, 0.34-0.76]), and POP (aHR, 0.28 [95% CI, 0.19-0.42]) compared to spontaneous vaginal delivery.
• On the other hand, operative vaginal delivery was related to significantly higher hazard of AI (aHR, 1.75 [95% CI, 1.14-2.68]) and POP (aHR, 1.88 [95% CI, 1.28-2.78]).
• Hazard ratios for POP, stratifying by delivery mode, were 3.0 ( 95% CI, 1.7-5.3) for a genital hiatus of 3 cm and 9.0 ( 95% CI, 5.5-14.8) for a genital hiatus of more than or equal to 3.5 cm (95% CI, 5.5-14.8).