Transperineal Ultrasound Immediately After Birth to Predict Postpartum Anorectal Dysfunction: A Prospective Cohort Study.

Introduction and hypothesis: To study the correlation between transperineal ultrasound (TPUS) findings immediately after birth and postpartum anal incontinence (AI) and constipation.

Methods: This is a prospective cohort study in pregnant patients who delivered vaginally at term. Participants filled in questionnaires, including the St. Mark's Incontinence Score and the Patient Assessment of Constipation Symptoms, at inclusion and at 6-weeks postpartum follow-up. TPUS acquisitions were performed immediately after birth to detect anal sphincter and levator defects, the dimensions of the genital hiatus as well as the dimensions of rectovaginal septum defects. We report on the prevalence and severity of AI and constipation at the postpartum follow-up and ran regression models to quantify the association between the former and TPUS findings immediately after birth. We calculated that a minimum of 156 patients were required to detect potential predictors for AI (power = 80%; alpha = 0.05; f² = 0.15).

Results: Of 182 consecutive participants, 109 (60%) reported AI and 78 (43%) constipation. There were 37 (20.3%) women with a levator avulsion, 83 (46%) with an external anal sphincter defect in one or more TUI-sections and 29 (16%) with a rectovaginal septum defect. On univariate regression, sphincter defects were associated with AI [OR = 1.94(1.28-2.94)]. On multivariate regression, levator avulsion was the only independent sonographic predictor of AI [aOR = 2.57(1.03-7.44)], whereas sphincter defects, dimensions of the genital hiatus or rectovaginal defects were not correlated with AI. We identified no factors associated with constipation.

Conclusions: The presence of levator avulsion immediately after vaginal delivery predicts postpartum AI. Ultrasound appearance of the anal sphincter, genital hiatus and rectovaginal septum was not informative.