Title: The POOL Study. Establishing the safety of waterbirth for mothers and babies: A cohort study with nested qualitative component
Funder: Health and Care Research Wales (Welsh Government)

Abstract: The POOL Study is a cohort study with a nested qualitative component. The primary study aim is to establish whether for ‘low-risk’ women who use a pool during labour, waterbirth, compared to leaving a pool prior to birth, is as safe for mothers and babies. Primary study objectives are to: 1) Evaluate if waterbirth is associated with an increase in adverse neonatal outcomes or treatment, to include asphyxia, infection, respiratory difficulties, and mortality; or maternal morbidity, particularly complex perineal trauma (Obstetric Anal Sphincter Injuries (OASIS)) and haemorrhage; 2) Assess the primary safety outcomes amongst the subgroups of nulliparous and parous women who were low risk at labour onset and 3) Describe outcomes, including the rates and required management of haemorrhage, amongst women who following birth in water, intend, and do not intend, to deliver the placenta underwater. To set pool use and waterbirth in the context of NHS care we will describe the overall proportion of women that use a pool for labour or birth and describe the characteristics of, and outcomes for, women with identified risk factors that use a pool during labour. Secondary study objectives are to: 1) Describe the rates, indications and outcomes of women requiring obstetric care during or following pool use during labour; 2) Explore factors associated with high and low rates of pool use in individual maternity units and 3) Calculate proportions, and describe the demographic and obstetric characteristics, of women using a birth pool for labour and birth. Many of the data items required to answer the commissioning brief, including babies partially born in water, cord snapping and delivery of the placenta in water, are not currently captured in maternity information systems, nor are they captured in any other routine data sources, such as HES or the national Maternity Services Data Set held by NHS Digital. Data items essential to answer the commissioning brief but not currently collected or available have been identified. To maximise efficiency of data collection these data items will be added to the electronic data systems at participating sites at the time of site opening in the summer of 2018. The addition of these essential data items will be followed by a 30 month period of prospective data capture, ending in November 2020. Where data relevant to aspects of the commission brief are already collected, this will be utilised to maximise study power. These variables include those required to assess the relationship between waterbirth and perineal trauma. For this outcome retrospective data, captured between January 2015 and site opening will be extracted and combined with prospective data covering the period from site opening to November 2020. To answer all research objectives approximately 600,000 individual computerised maternity records held on secure NHS servers at around 30 NHS sites, covering the period January 2015 to November 2020 will be extracted. The study will include maternity units in England and Wales which currently use the EuroKing® maternity information system. All maternity units using EuroKing® also provide individual level data to the National Neonatal Research Database (NNRD) enabling matching between maternity and neonatal morbidity outcome data. As previously requested by the Board a qualitative component of the study, will explore the influence of maternity unit culture on rates of pool use and waterbirth.

Lay abstract: It is estimated that up to 60,000 (9 in every 100) babies are born into water annually in the UK and with encouragement from NICE for maternity units to provide birthing pools for women, this number may increase further. Women use a birth pool during labour for pain relief, and some women choose to remain in the pool for the birth of their baby. Over the years there have been reports of babies that had breathing difficulties or infection following birth in water, and there is a concern that women that have a waterbirth more often sustain severe trauma to their vaginal area or have unrecognised heavy bleeding. Despite concern, and some reports in the press, to date there have not been studies large enough to show whether or not waterbirth causes an increase in these poor outcomes for mothers or their babies. This study plans to answer the question about the safety of waterbirths. The study will collect data on the births of all women in around 30 maternity units during 2015-2020. The study will see how many women are using birth pools, how many women give birth in water and whether mothers or their babies come to any extra harm as a result of waterbirth. The study will include women giving birth to their first baby and women giving birth to a subsequent child. The study needs to collect information on 15,000 waterbirths and 15,000 births out of water. To do this without disturbing women in labour or just after birth, when they are looking after their new baby, the study will use information collected as part of each woman’s and linked baby maternity record stored at hospitals in computerised systems. For babies that need specialist care after birth, the study will also use data held by the National Neonatal Research Database. Some of the data needed for this study is already collected by maternity units, so data from births from 2015 onwards can be included in the study. However, as some important information needed to fully answer the study questions, such as how many babies have antibiotics, and how many women deliver the placenta underwater, is currently not collected, some new items will be added to maternity computer systems when the study starts in 2018. To keep women’s information confidential, the data stored in existing maternity information systems will have identifying information, such as names, addresses and NHS numbers removed before the information is sent to the research team in Cardiff for analysis. Professionals and parents have strong opinions on waterbirth. Some are great advocates, who promote the potential benefits of waterbirth to women, whilst others remain concerned that women may be taking additional unnecessary risks by giving birth in water. The diversity of opinions towards waterbirth makes it particularly important that the study team have representatives from all interested groups. The professionals on the study team include midwives, an obstetrician and a neonatologist as well as the experts needed to deliver this large complex study. The NCT is the largest parenting organisation in the UK and have joined the study team as have the Royal College of Midwives. The study will produce academic papers and evidence based information for women and their partners on waterbirth. The study findings will be of great interest and would be expected to generate much press interest, and quickly influence the information provided to pregnant women throughout the UK.

Research activity codes: 6.8 COMPLEMENTARY
Health categories: REPRODUCTIVE HEALTH AND CHILDBIRTH