Associations among umbilical midline diastasis severity, abdominal wall function, and quality of life in postpartum women with diastasis recti abdominis

Background Obstetric diastasis recti abdominis (DRA), a common postpartum public health issue, often has its effects on maternal function and quality of life underestimated. Clarifying the correlation between its separation degree and related indicators is urgent to support rehabilitation management. Objective To explore the correlations among umbilical rectus abdominis separation distance, abdominal wall muscle strength, low back pain disability, and quality of life in postpartum women to provide evidence for constructing a DRA postpartum rehabilitation pathway based on the integration of sports and health. Methods A total of 46 postpartum women with sonographically diagnosed obstetric DRA were enrolled. Portable ultrasonography was used to measure DRA distance at five abdominal sites and muscle thickness at six abdominal sites. Meanwhile, abdominal wall muscle strength was assessed, and the Oswestry Disability Index (ODI), HerQles Questionnaire, and SF-36 Health Survey were completed. Spearman correlation analysis and Kruskal–Wallis test were applied for subgroup comparisons. The test level was set at α = 0.05. Results Results showed that the median resting diastasis distance at the umbilical midpoint (M3) was 48.5 mm. M3 was negatively correlated with abdominal wall muscle strength (r = −0.405, p = 0.005) and positively correlated with ODI (r = 0.387, p = 0.008) and total HerQles score (r = 0.405, p = 0.005) and had no significant correlation with SF-36 scores. In the exploratory tertile-based subgroup analysis, the subgroup with the largest separation—the upper tertile of the sample (approximately M3 IRD >55 mm)—showed lower abdominal wall muscle strength (p = 0.009) and higher ODI scores (p = 0.016) than the other subgroups. M3 showed a nominal positive correlation with the thickness of the right transversus abdominis (r = 0.300, unadjusted p = 0.043); however, this association did not remain significant after FDR correction. Conclusion Ultrasonography combined with disease-specific scales, including ODI and HerQles, is recommended as assessment tools for DRA. Rehabilitation interventions should focus on the coordinated training of the core muscle group to address this public health issue.