Neuromuscular Function Patterns at 6 Weeks Postpartum Characterised Using Latent Profile Analysis: A Cross-Sectional Study of 525 Women.

INTRODUCTION AND HYPOTHESIS: Postpartum pelvic floor dysfunction is heterogeneous; routine assessment often uses single modalities that may miss neuromuscular variation. We explored whether multimodal pelvic-floor assessment at 6 weeks postpartum could identify exploratory neuromuscular clusters using latent profile analysis (LPA) in a single-centre retrospective cohort. METHODS: Retrospective cross-sectional study of de-identified routine ≈6-week postpartum records from one Chinese public hospital (January 2024-December 2025; n = 525), with Glazer-protocol surface electromyography (sEMG), transperineal ultrasound, Oxford strength grading and patient-reported outcomes. After correlation-based variable reduction, LPA used Gaussian mixture models; models were selected using the Bayesian information criterion, entropy, minimum class proportion and bootstrap stability. Between-pattern differences were assessed with rank-based tests and Spearman correlations. RESULTS: A two-class equal volume, equal shape and variable orientation solution was selected (Pattern 1, n = 60 [11.4%]; Pattern 2, n = 465 [88.6%]). Pattern 1 had lower resting sEMG and higher Oxford strength than Pattern 2 (e.g. pre-contraction mean 4.2 vs 7.8 µV). Fifteen of the 16 neuromuscular and strength indicators differed between patterns. Pelvic-floor pain differed (p < 0.001); Pelvic Floor Distress Inventory-20 (p = 0.129), Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire-12 (p = 0.616) and stress urinary incontinence (18.3% vs 23.0%; p = 0.580) did not. Pain correlated with resting sEMG (Spearman ρ = 0.56, p < 0.001). CONCLUSIONS: At 6 weeks postpartum, exploratory clustering differed mainly in sEMG, strength and pelvic pain, not in distress or incontinence scores. Resting sEMG correlated with pain and should not be equated with hypertonicity without longitudinal validation. Prospective studies are needed before clinical implementation.