The use of forceps, a prolonged second stage, and obstetric anal sphincter tears were associated with levator avulsion. There were no associated intrapartum predictors for hiatal overdistension.

Objective Vaginal childbirth may result in levator ani injury secondary to overdistension during the second stage of labour. Other injuries include perineal and anal sphincter tears. Antepartum use of a birth trainer may prevent such injuries by altering the biomechanical properties of the pelvic floor. This study evaluates the effects of Epi-No â use on intrapartum pelvic floor trauma.Design Multicentre prospective randomised controlled trial.Setting Two tertiary obstetric units in Australia.Population Nulliparous women carrying an uncomplicated singleton term pregnancy.Methods Participants were assessed clinically and with 4D translabial ultrasound in the late third trimester, and again at 3-6 months postpartum. Women randomised to the intervention group were asked to use the Epi-No â device from 37 weeks of gestation until delivery.

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