The natural history of levator avulsion one year following childbirth: a prospective study

ObjectiveTo explore the natural history of levator avulsion in primipara 1year postpartum and correlate this to pelvic floor dysfunction (PFD). DesignObservational longitudinal cohort study. SettingDistrict General University Hospital. Population or sampleNullipara at 36weeks of gestation, 3months and 1year postpartum. MethodsValidated methods assessed muscle strength, prolapse, ultrasound measurements of levator hiatus and avulsion, and questionnaires for sexual function, and urinary and anal incontinence. Pattern differences over time were evaluated using linear mixed models. Main outcome measuresNatural history of levator avulsion and relationship with PFD. ResultsOf the 269 nullipara, 191 returned at 3months and 147 (55%) at 1year postpartum; 109 had a vaginal delivery and 38 had a caesarean delivery. Sixty-two percent (n=13/21; 95% CI 41-79%) of levator avulsions diagnosed 3months postpartum were no longer evident at 1year. Following vaginal delivery, nine women (8%, 95% CI 4.2-15.1%) had persistent levator avulsion. Most changes in PFD occurred between the antenatal and first postnatal visit, without improvement at 1year. Women with persistent levator avulsion had significantly worse deterioration patterns of muscle strength, hiatus measurements and vaginal symptoms (loose vagina/lump sensation). However, evidence of PFD was also related to no longer evident levator avulsion. ConclusionsSixty-two percent of levator avulsions were no longer evident 1year postpartum. Partial avulsion has a tendency to improve over time, which seems to be less common for complete levator avulsions. Women with no longer evident and persistent levator avulsion had PFD, with worse patterns in presence of persistent avulsion.