Change in prevalence of major levator ani muscle defects from 6 weeks to 1 year postpartum, and maternal and obstetric risk factors: A longitudinal ultrasound study.

There was a 50% reduction of sonographically diagnosed major LAM defects from 6 weeks to 1 year postpartum. This finding suggests that assessment of the major LAM 6 weeks postpartum may be too early to diagnose defects/avulsions. Long second stage of labor, high neonatal birthweight and vacuum delivery were associated with persistent major LAM defects/avulsions.