Randomised clinical trial of a laxative alone versus a laxative and a bulking agent after primary repair of obstetric anal sphincter injury

Abstract

Objective: To compare two postpartum laxative regimens in women who have undergone primary repair of obstetric anal sphincter injury.

Design: Randomised controlled trial.

Setting: National Maternity Hospital, Dublin.

Population: A total of 147 postpartum women who had sustained anal sphincter injury at vaginal birth.

Methods: Women were randomised to receive either lactulose alone thrice daily for the first three postpartum days followed by sufficient lactulose to maintain a soft stool over the following 10 days (lactulose group, n = 77) or the lactulose regimen combined with a sachet of ispaghula husk daily for the first 10 postpartum days (Fybogel group, n = 70). All patients kept a diary of bowel habit for the first 10 postpartum days and were invited to return for review at 3 months postpartum.

Main outcome measures: Patient discomfort with first postpartum bowel motion, incidence of postnatal constipation and incontinence and incontinence score in postnatal period.

Results: Pain scores were similar in the two treatment groups; but incontinence in the immediate postnatal period was more frequent with the two preparations compared with lactulose alone (32.86% versus 18.18%, P = 0.03).

Conclusions: This study does not support routine prescribing of a stool-bulking agent in addition to a laxative in the immediate postnatal period for women who have sustained anal sphincter injury at vaginal delivery.