Can levator avulsion be predicted antenatally?

Objective: We sought to determine whether antepartum prediction of major levator trauma is feasible. Study Design: A prospective longitudinal study was undertaken on 488 pregnant nulliparous women seen between 36-38 weeks and again 4 months after delivery. All underwent an interview and 4-dimensional transperineal ultrasound. Diagnosis of levator trauma (avulsion) on tomographic ultrasound was correlated with predelivery demographic variables and ultrasound parameters. Results: In all, 367 women returned for postpartum assessment after normal vaginal delivery (n = 187), vacuum/forceps (n = 54), and cesarean section (n = 126). Avulsion was diagnosed in 34 vaginally parous women (14%). Maternal age, family history of cesarean section, hiatal dimensions, levator muscle strain, bladder neck descent, and subpubic arch angle were not associated with avulsion. The only predictor identified was a lower body mass index (P = .005). Conclusion: Antepartum prediction of major levator trauma may be difficult or impossible. Future studies should focus on modification of current obstetric practices and antepartum interventions applicable to the general population.