Risks of pelvic organ prolapse and urinary incontinence increase after the first vaginal delivery. During the early postpartum period, a time of active regeneration and healing of the pelvic floor, women may be particularly vulnerable to greater pelvic floor loading.

This prospective cohort study aimed to determine whether objectively measured moderate to vigorous physical activity in the early postpartum period predicts pelvic floor support and symptoms 1 year after the first vaginal birth.

We enrolled nulliparous women in the third trimester, later excluding those who had a cesarean or preterm delivery. Participants wore triaxial wrist accelerometers at 2 to 3 weeks and 5 to 6 weeks postpartum for ≥4 days. Primary outcomes, assessed 1 year postpartum, included (1) pelvic floor support on Pelvic Organ Prolapse Quantification examination, dichotomized as maximal vaginal descent of <0 cm (better support) vs ≥0 cm (worse support); and (2) pelvic floor symptom burden, considered positive with report of ≥1 bothersome symptom in ≥2 of 6 domains, assessed using the Epidemiology of Prolapse and Incontinence Questionnaire. The primary predictor was average daily moderate to vigorous physical activity. Because we could not eliminate women with pelvic floor changes before pregnancy, we modeled prevalence, rather than risk, ratios for each outcome using modified Poisson regression.

Of 825 participants eligible after delivery, 611 completed accelerometry and 1-year follow-up; 562 completed in-person visits, and 609 completed questionnaires. The mean age was 28.9 years (standard deviation, 5.01). The mean for moderate to vigorous physical activity measured in minutes per day was 57.3 (standard deviation, 25.4) and 68.1 (standard deviation, 28.9) at 2 to 3 weeks and 5 to 6 weeks, respectively. One year postpartum, 53 of 562 participants (9.4%) demonstrated worse vaginal support and 330 of 609 participants (54.2%) met criteria for pelvic floor symptom burden. In addition, 324 (53.1%), 284 (46.6%), 144 (23.6%), and 25 (4.1%) reported secondary outcomes of stress urinary incontinence, overactive bladder, anal incontinence, and constipation, respectively, and 264 (43.4%), 250 (41.0%), and 89 (14.6%) reported no, mild, or moderate to severe urinary incontinence, respectively.

The relationship between moderate to vigorous physical activity and outcomes was not linear. On the basis of plots, we grouped quintiles of moderate to vigorous physical activity into 3 categories: first and second quintiles combined, third and fourth quintiles combined, and fifth quintile. In final multivariable models, compared with women in moderate to vigorous physical activity quintiles 3 and 4, those in the lower 2 (prevalence ratio, 0.55; 95% confidence interval, 0.31–1.00) and upper quintile (prevalence ratio, 0.70; 95% confidence interval, 0.35–1.38)) trended toward lower prevalence of worse support. However, we observed the reverse for symptom burden: compared with women in quintiles 3 and 4, those in the lower 2 (prevalence ratio, 1.20; 95% confidence interval, 1.02–1.41) and upper quintile prevalence ratio 1.34 (95% confidence interval, 1.11–1.61) demonstrated higher prevalence of symptom burden.

Moderate to vigorous physical activity did not predict any of the secondary outcomes. The presence of a delivery factor with potential to increase risk for levator ani muscle injury did not modify the effect of moderate to vigorous physical activity on outcomes.

Except for support, which was worse in women with moderately high levels of activity, early postpartum moderate to vigorous physical activity was either protective or had no effect on other parameters of pelvic floor health. Few women performed substantial vigorous activity, and thus, these results do not apply to women performing strenuous exercise shortly after delivery.