3D Endovaginal Ultrasound after Delivery: New Clinical and Ultrasound Insights into Levator Ani Lesions: A Prospective Single-Center Study.

OBJECTIVES

To determine the incidence of complete and partial levator ani muscle (LAM) lesions using 3-dimensional endovaginal ultrasound (3D-EVUS) at 3-months postpartum in low-risk primiparous women and evaluate associations with perineal outcomes and early urogynecological parameters.

METHODS

Prospective interventional study of primiparous women with spontaneous vaginal delivery (March 2021-May 2023) at a tertiary urogynecology center in Rome, Italy (LATA protocol, IRB: 4202).

INCLUSION CRITERIA: >37 weeks, age 18-45 years, body mass index (BMI) ≥20, physiologic pregnancy.

EXCLUSION CRITERIA: age >45, BMI <20, fetal macrosomia >4500 g, forceps delivery. Perineal outcomes were recorded at delivery. Participants underwent 3D-EVUS and urogynecological assessment evaluating pelvic floor muscle function, command inversion, recruitment of auxiliary muscles, and hypertonicity at 3-months postpartum. LAM lesions were classified as partial (asymmetry, irregularity, ballooning) or complete/avulsion (detachment from pubic bone). Statistical analysis included logistic regression.

RESULTS

Of 350 eligible patients, 202 completed follow-up. At 3D-EVUS, 52% had no LAM lesions, 45% had partial lesions, 3% had avulsions. Intact perineum was observed in 16.2% without LAM lesions, 4.4% with partial lesions, 0% with avulsion (p = .018). Lacerations were more frequent with partial LAM lesions (73.6%) versus no lesion (59.0%) and avulsion (33.3%) (p = .027). Command inversion was associated with LAM lesions (p = .004). Urogenital hiatal area under Valsalva independently predicted LAM lesions (p < .001), with area >20.8 cm2 demonstrating 82% specificity and 45% sensitivity.

CONCLUSIONS

3D-EVUS enables the detection of subtle lesions frequently missed by conventional approaches. Partial LAM lesions are common in primiparous women after low-risk delivery, while avulsions remain rare. Command inversion and enlarged urogenital area provide valuable markers for early detection and intervention.