Impact of childbirth mode and interaction of multiple factors on pelvic floor function: a comprehensive analysis of postpartum muscle strength indicators.

PURPOSE: Based on electrophysiological assessment data of pelvic floor muscles from 1,781 women, this study systematically analyzes the association patterns among obstetric history, anthropometric indicators, and pelvic floor function through hierarchical regression modeling, aiming to provide a novel perspective for precise risk assessment.

METHODS: A retrospective analysis was conducted on data from 1,781 adult women, including age, height, weight, BMI, childbirth history, and pelvic floor screening results. Participants were grouped based on pelvic floor screening scores (above or below 80) and childbirth method (vaginal childbirth or cesarean section). Multiple linear regression was used to analyze risk factors for pelvic floor dysfunction, while t-tests, analysis of covariance, and Mann-Whitney U-tests were employed to assess the significance of differences between groups.

RESULTS: Patients were divided into two groups based on pelvic floor screening scores (≥80 and <80). There were statistically significant differences between the <80 group and ≥80 group in age, weight, and BMI (age: 38.73 ± 9.95 years vs. 37.03 ± 8.27 years, weight: 57.26 ± 16.63 kg vs. 55.69 ± 7.22 kg, BMI: 22.67 ± 6.72 vs. 21.88 ± 2.56 kg/m², all p < 0.05). After adjusting for age, weight, height, and BMI, differences in time since the last childbirth to the current screening were also observed (7.20 ± 9.69 years vs. 4.78 ± 7.99 years, p < 0.05). Significant differences in weight were noted between the vaginal childbirth and cesarean section groups (56.32 ± 8.8 kg, P < 0.05 vs. 59.59 ± 30.50 kg, P < 0.05). After adjusting for the effects of age, weight, height, and BMI, the two groups showed statistically significant differences in the total score (cesarean section 66.13 ± 14.71 vaginal delivery 63.01 ± 16.69, p = 0.021), pre-resting stage score (cesarean section 51.28 ± 27.27, vaginal delivery 62.47 ± 25.04, p = 0.000), fast-twitch (Type II fibers) stage score (cesarean section 78.89 ± 18.21, vaginal delivery 72.76 ± 22.38, p = 0.001), slow-twitch (Type I fibers) stage score (cesarean section 60.93 ± 25.39, vaginal delivery53.21 ± 26.55, p = 0.000), post-resting stage score (cesarean section 53.21 ± 26.55, vaginal delivery 60.93 ± 25.39, p = 0), and time from the last childbirth to the current screening (cesarean section 7.27 ± 10.04, vaginal delivery 5.03 ± 6.46, p = 0.001). Pelvic floor screening total score was negatively correlated with the time since the last childbirth (B = -0.233, Beta = -0.135, p = 0.013) and number of deliveries (B = -1.511, Beta = -0.078, p = 0.022), while positively correlated with height (B = 1.447, Beta = 0.437, p = 0.043).

CONCLUSION: Multiple deliveries and longer inter-delivery intervals cumulatively impair pelvic floor function. Individualized rehabilitation should prioritize women with shorter stature, older age, or multiple births, alongside promoting a healthy BMI rather than weight loss alone. Postpartum training should be mode-tailored: activating after vaginal birth, relaxing after cesarean.