Introduction and Hypothesis: Obstetric Anal Sphincter Injury (OASI) during childbirth is associated with urino-genital pain and dysfunction. Waterbirth is a popular birth choice for women, but controversy remains around the risk of OASI during waterbirth. This study reports on the incidence of OASI, and factors associated with OASI, for a cohort of women who gave birth in water. Methods: This secondary analysis used prospectively collected data from 2,908 women who gave birth in water in the hospital setting. Incidence of OASI was calculated. Univariable and multivariable logistic regression analysis evaluated factors associated with OASI. Results: The incidence of OASI was 1.9% (95% CI 1.4, 2.4) for all women. In nulliparae it was higher (3.2%, 95% CI 2.3, 4.3), than for multiparae (0.9%, 95% CI 0.5, 1.4). In the multivariable analysis two variables were associated with OASI; multiparity was negatively associated with OASI (aOR 0.24, 95% CI 0.12, 0.50, p < 0.001), and birth weight was positively associated with OASI (aOR 1.001, 95% CI 1.000, 1.002, p = 0.02). A ‘hands-on’ technique was used during only 13% of births. Birth position supporting a flexible sacrum did not influence OASI risk. Conclusions: A low incidence of OASI was found for this cohort of women. The low proportion of midwives using a hands-on technique suggests that it may not be required in waterbirth.
Burns, Ethel Price, LauraCarpenter, Jane Smith, Lesley
Department of Nursing
Year of publication: 2019Date of RADAR deposit: 2019-10-21