Pelvic floor healing milestones after obstetric anal sphincter injury: a prospective case control feasibility study

Severe perineal tears can predict bothersome pelvic floor disorders later in life. We have a poor understanding of pelvic floor changes during the third trimester and the first few postpartum months. We aimed to compare women with severe perineal trauma during childbirth with women who experienced minimal trauma, for condition-specific quality of life, sexual function, mental health and overall quality of life in the first 6 months postpartum.

We recruited primiparous women with third- or fourth-degree tears (obstetric anal sphincter injuries, OASIS) and age-matched controls with no tears or first-degree tears in the immediate postpartum period. Participants completed validated questionnaires at baseline, 2, 4 and 6 months postpartum. Mixed effects linear regression or quantile regression adjusted for baseline score were used to compare the groups as appropriate.

A total of 74 women completed at least one questionnaire (35 OASIS, 39 controls). Both groups had similar demographics. Women with OASIS tended to have worse Pelvic Floor Distress Index-40 scores at month 2; median scores were similar in the two groups by month 6. They also had significantly lower Female Sexual Function Index scores (mean difference: -6.1; 95% CI: -11.9, -0.2, p=0.043) at month 2. There were no mental health group differences and quality of life improved over time, mainly in the OASIS group. Six-month participant attrition rate was 52%.

Women with OASIS encounter specific pelvic floor challenges during the first 6 months postpartum. Although our recruitment rate was high, the attrition rate was also high, demonstrating challenges with retention of postpartum women into longitudinal research.