Risk factors and interaction analysis of severe diastasis recti abdominis within 6 months postpartum

Severe diastasis recti abdominis (DRA) in the postpartum period may lead to long‑term functional impairment in women. However, the independent effects and interactions of perinatal risk factors during the early postpartum recovery window have not been fully elucidated. This study aims to analyze the risk factors and interaction effects associated with severe postpartum DRA and to identify characteristics of high‑risk populations.

This retrospective cohort study included postpartum women who underwent postpartum rehabilitation treatment at Hengyang Maternal and Child Health Hospital between January 2019 and August 2022, with a postpartum interval of 42 to 180 d. The inter-rectus distance was measured using palpation combined with caliper assessment. According to the inter-rectus distance, participants were divided into 4 groups: A severe DRA group (separation distance ≥4 cm), a moderate DRA group (3.0 to 3.9 cm), a mild DRA group (2.0 to 2.9 cm), and a normal group (<2 cm). The moderate DRA, mild DRA, and normal groups were combined as the control group. Receiver operating characteristic (ROC) curve analysis was used to evaluate continuous variables and determine optimal cutoff values for stratification. The chi-square test was used to compare differences in influencing factors between the severe DRA group and the control group. Binary Logistic regression analysis was further performed to investigate the effects of various factors on severe DRA, and interaction analysis within the binary Logistic regression model was used to identify high-risk populations.

A total of 525 postpartum women were ultimately included, including 112 in the severe DRA group, 257 in the moderate DRA group, 98 in the mild DRA group, and 58 in the normal group. The overall incidence of DRA was 89.0%, while the incidence of severe DRA was 21.3%. The diagnostic cutoff values for body mass index (BMI), neonatal birth weight, and gestational weight gain were 22.55 kg/m², 3 350 g, and 12.25 kg, respectively. Participants with BMI ≥22.55 kg/m², neonatal birth weight ≥3 350 g, gestational weight gain ≥12.25 kg, multiparity, cesarean delivery, or number of fetuses ≥2 had significantly higher incidences of severe DRA (all P<0.05). Binary Logistic regression analysis showed that neonatal birth weight ≥3 350 g, gestational weight gain ≥12.25 kg, cesarean delivery, and multiparity were independent risk factors for severe DRA (all P<0.05). The interaction among neonatal birth weight ≥3 350 g, multiparity, and cesarean delivery showed the strongest association with severe DRA (OR=7.10, 95% CI 3.43 to 14.71). When all 3 risk factors were present simultaneously, the incidence of severe DRA reached 61.76%.

Neonatal birth weight ≥3 350 g, gestational weight gain ≥12.25 kg, cesarean delivery, and multiparity are important independent risk factors for severe postpartum DRA, and significant synergistic amplification effects exist among these factors. This study clarified the characteristics of high-risk populations and may provide a basis for targeted early screening and intervention.