The POOL study
Research type
Research Study
Full title
The POOL study: Establishing the safety of waterbirth for mothers and babies: A cohort study with nested qualitative component.
IRAS ID
238743
Contact name
Julia Sanders
Contact email
Sponsor organisation
Cardiff University
Clinicaltrials.gov Identifier
35159 , ISRCTN
Duration of Study in the UK
3 years, 5 months, 0 days
Research summary
Research Summary
Annually 9/100 UK vaginal births are waterbirths, and this proportion may increase further. Birthing pools are used during labour for pain relief, and some women remain in the pool for the birth. There have been reports of infants having breathing difficulties or infection following birth in water, and there is concern that women that have a waterbirth may more often sustain severe trauma to their vaginal area or have unrecognised heavy bleeding. To date there have not been studies large enough to show whether or not waterbirth causes an increase in these poor maternal/infant outcomes.\n \nData will be collected on the births of all women in ~30 Maternity Units (2015-2020).\nThe study will find out: \n• number of women who use birth pools\n• number of waterbirths\n• Whether mothers/infants come to any extra harm as a result of waterbirth\n\nData are required on: \n• 15,000 waterbirths \n• 15,000 births out of water\n\nRoutinely collected data will be used. For infants needing specialist care, data will be retrieved from the National Neonatal Research Database (NNRD). Some data needed for this study are already collected by Maternity Units, so data from births 2015-2018 can be included in the study. To answer the questions some new variables are required (to be added in 2018). Information about both mothers/infants will remain confidential, the data stored on existing information systems will have identifying information removed before being sent to the research team in Cardiff for analysis. \n\nThe qualitative component will use a two-stage approach to identify and explore the influence of cultural factors, through collection and analysis of group and 1:1 interviews with a range of professional and lay stakeholders. \nKey research questions: \n• What factors influence birth pool use in units with high/low waterbirth rates? \n• What factors influence giving birth in water in units with high/low waterbirth rates?
Summary of Results
We wanted to know if waterbirths in the UK are as safe as giving birth out of water for women and their babies at low risk of complications. Using a birth pool, or bath, is an increasingly popular choice of pain relief in labour but some midwives and doctors were concerned that waterbirths could carry risks. There were reports of babies becoming seriously ill, or even dying, after waterbirths, and that mothers were more likely to have severe tears or heavy blood loss, but no major UK research to confirm this.
Our study, called POOL, looked at the NHS records of 87,040 women who used a pool in labour between 2015 and 2022, across 26 NHS trusts. We compared women who gave birth in water to those who left the pool for extra medical care or more pain relief. Most of the women who got out of the pool for extra medical care were first time mothers (1 in 3 compared to 1 in 20 of the women who had previously given birth). We looked at rates of severe tears experienced by women, and rates of babies dying, needing antibiotics or help with their breathing.
Overall, we found that around half of all women who used a pool in labour had a waterbirth. The rate of problems was very similar in waterbirths and births out of water. Around 1 in 20 first time mothers, and 1 in 100 mothers having their second, third or fourth baby had a severe tear. Around 3 in every 100 babies needed antibiotics or help with their breathing after birth, and baby deaths were rare.
The POOL Study concluded that for low-risk women giving birth in the NHS, having a waterbirth is as safe for them and their babies as leaving the water before birth.
REC name
Wales REC 3
REC reference
18/WA/0291
Date of REC Opinion
18 Sep 2018
REC opinion
Favourable Opinion