Background: Postpartum recovery from pelvic floor trauma associated with vaginal delivery may be impaired by the transient hypoestrogenic state associated with breastfeeding.
Objective: The aim of our study was to examine the association between exclusive breastfeeding and pelvic floor disorders 1-2 decades after the first vaginal delivery. We hypothesize that compared with women who did not breastfeed following vaginal delivery, women who breastfeed would have a higher proportion of pelvic floor disorders s, and those women who practiced sustained exclusive/unsupplemented breastfeeding would have the highest proportion.
Study design: This is a secondary analysis of the Mothers' Outcomes After Delivery study, a prospective cohort study of pelvic floor disorders after childbirth. Participants were recruited 5-10 years after their first delivery and followed up annually for up to 9 years. This analysis focused on participants who experienced at least 1 vaginal delivery. Each participant completed a self-administered questionnaire regarding breastfeeding. Based on questionnaire responses, breastfeeding status was classified into 3 ordinal categories: unexposed (did not breastfeed or breastfed <1 week); limited exclusive breastfeeding (breastfed without supplementation for ≥1 week but <12 weeks); and sustained exclusive breastfeeding (unsupplemented breastfeeding ≥12 weeks). Our primary outcomes of interest were the proportions of stress urinary incontinence, anal incontinence, and pelvic organ prolapse. The outcomes of interest were defined using the Epidemiology of Prolapse and Incontinence Questionnaire and the Pelvic Organ Prolapse Quantification Examination at enrollment and annually for up to 9 years thereafter. Additionally, a subanalysis examined the relationship between breastfeeding and anal incontinence in an obstetric anal sphincter injury-specific population. Generalized estimating equations were utilized to determine the relationship between breastfeeding and the outcomes of interest.
Results: Among 705 women, 189 (27%) were classified as unexposed, 145 (20%) were categorized as limited exclusive breastfeeding, and the remaining 371 women (53%) met our definition of sustained exclusive breastfeeding. Median follow-up was 5 years, contributing to a total of 3079 person years. The proportion of each pelvic floor disorder, based on 3079 person-years of follow-up was: stress urinary incontinence (27%), pelvic organ prolapse (20%), or anal incontinence (25%). Using generalized estimating equations adjusting for race, education, parity, and body mass index, sustained exclusive breastfeeding was not significantly associated with stress urinary incontinence (adjusted odds ratio, 0.82, 95% confidence interval, 0.55-1.23), pelvic organ prolapse (adjusted odds ratio, 0.78, 95% confidence interval, 0.49-1.26), and anal incontinence (adjusted odds ratio, 0.67, 95% confidence interval, 0.44-1.00). Regarding our obstetric anal sphincter injury subanalysis, 123 women within our cohort experienced obstetric anal sphincter injuries at delivery. Anal incontinence was reported in 32% of these women. However, there was no observed relationship between breastfeeding and the development of anal incontinence during study follow-up in this population.
Conclusion: Breastfeeding after vaginal childbirth was not associated with the development of stress urinary incontinence, pelvic organ prolapse, or anal incontinence 1-2 decades after the first vaginal delivery.
Keywords: anal incontinence; breastfeeding; pelvic floor disorders; pelvic organ prolapse; stress urinary incontinence.
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