Maternal and neonatal outcomes following waterbirth: a cohort study of 17 530 waterbirths and 17 530 propensity score-matched land births.

OBJECTIVE: Investigate maternal and neonatal outcomes following waterbirth.

DESIGN: Retrospective cohort study, with propensity score matching to address confounding.

SETTING: Community births, United States.

SAMPLE: Medical records-based registry data from low-risk births were used to create waterbirth and land birth groups (n = 17 530 each), propensity score-matched on >80 demographic and pregnancy risk covariables.

METHODS: Logistic regression models compared outcomes between the matched waterbirth and land birth groups.

MAIN OUTCOME MEASURES: Maternal: immediate postpartum transfer to a hospital, any genital tract trauma, severe (3rd/4th degree) trauma, haemorrhage >1000 mL, diagnosed haemorrhage regardless of estimated blood loss, uterine infection, uterine infection requiring hospitalisation, any hospitalisation in the first 6 weeks. Neonatal: umbilical cord avulsion; immediate neonatal transfer to a hospital; respiratory distress syndrome; any hospitalisation, neonatal intensive care unit (NICU) admission, or neonatal infection in the first 6 weeks; and neonatal death.

RESULTS: Waterbirth was associated with improved or no difference in outcomes for most measures, including neonatal death (adjusted odds ratio [aOR] 0.56, 95% CI 0.31-1.0), and maternal or neonatal hospitalisation in the first 6 weeks (aOR 0.87, 95% CI 0.81-0.92 and aOR 0.95, 95% CI 0.90-0.99, respectively). Increased morbidity in the waterbirth group was observed for two outcomes only: uterine infection (aOR 1.25, 95% CI 1.05-1.48) (but not hospitalisation for infection) and umbilical cord avulsion (aOR 1.57, 95% CI 1.37-1.82). Our results are concordant with other studies: waterbirth is neither as harmful as some current guidelines suggest, nor as benign as some proponents claim.

TWEETABLE ABSTRACT: New study demonstrates #waterbirth is neither as harmful as some current guidelines suggest, nor as benign as some proponents claim. @TheUpliftLab @BovbjergMarit @31415926abc @NICHD_NIH.