Strengths and limitations
This is the first study of its kind to include women utilising WWI and waterbirth whilst using CEFM. These women represent a ‘moderate risk’ rather than the usual ‘low risk’ cohort that has dominated the literature until now. The safety and efficacy of WWI for labour and birth in low-risk women is well established (6, 8). This study adds to the current literature but also highlights that this practice is a safe option for some women with clearly defined, moderate risk factors who require CEFM in labour.
This is a large sample size relative to other studies, with 400 women using WWI during their labour and/or birth. The groups had similar baseline characteristics and the subgroup analysis allowed for the control of confounding factors. Our data was prospectively collected and inputted into the perinatal database at the time of birth thereby increasing the reliability of our findings.
Due to the nature of the intervention, patients self-select Waterbirth/WWI which may be a source of bias. A randomised controlled trial would reduce bias but would be challenging given it removes choice around pool access and birth setting. Despite the larger sample size, some secondary outcomes are relatively rare (i.e. cord avulsion), and the nonsignificant findings should be interpreted within the context of limited statistical power.
Our department has a clear, well-defined policy surrounding WWI/Waterbirth and an established midwifery education programme facilitating training of accoucheurs in waterbirth. The findings from this study may not be generalisable to water immersion protocols at sites whereby the policies and education surrounding WWI/Waterbirth are less established or differ significantly from our study site.