This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
Researchers analysed data on women without pregnancy complications who used a birthing pool during labour. Some women got out of the pool due to medical complications during labour or because they wanted pain relief that cannot be given in water.
Among women without labour complications, compared with leaving the pool to give birth, giving birth in the pool led to:
- no increase in serious tears (from vagina to anus)
- no increase in baby deaths, neonatal admissions with breathing support, or infections requiring antibiotics among babies.
The study could reassure women and healthcare professionals about the safety of water births. Clinicians could discuss these findings with pregnant women considering using a birthing pool during labour.
More information on waterbirths can be found on the NHS website.
The issue: are water births safe?
The National Institute for Health and Care Excellence (NICE) recommends birthing pools as a pain relief option during labour for women without pregnancy complications. Some women leave the water before birth, others give birth in the pool.
There have been reports of infections, newborn babies inhaling water, and higher rates of perineal tears during water births. While NICE has stated that the evidence is not strong enough to discourage these births, some professionals remain reluctant to promote water births.
This study explored the safety of giving birth in water.
What’s new?
The analysis included 60,402 women without pregnancy or labour complications who used a birthing pool during labour between 2015 – 2022 in the UK. 39,627 gave birth in the water and 20,775 gave birth out of the water.
Among women, the main outcome was serious perineal tears (from vagina to anus) during birth. Among babies, it was a combination of baby deaths in hospital, neonatal admissions with breathing support or antibiotics given into a vein.
Rates of most outcomes were the same with water births, compared with births out of water. The researchers found:
- no difference in the numbers of serious tears (2.5% water births; 3.8% births out of water)
- no difference in the combined outcome of baby deaths, neonatal admissions, or antibiotic prescriptions (2.7% water births; 4.4% births out of water).
Baby deaths were extremely rare in both groups (2 per 10,000 waterbirths; 3 per 10,000 births out of water). Few babies were admitted to a neonatal unit after birth (1.5% waterbirths; 0.8% births out of water) or needed intravenous antibiotics (1.8% waterbirths; 2.9% births out of water).
Among women who had given birth before, serious tears were less common with waterbirths (1.1%) than births out of water (1.7%). Among women giving birth to their first baby, the likelihood of tears was the same between groups. There was also no difference for most other outcomes: the mother bleeding, manually removing the placenta, delayed start to breastfeeding, or shoulder dystocia (when a baby's shoulder gets stuck behind the mother's pubic bone).
Umbilical cord snapping (which can abruptly stop the flow of blood to the baby) was more common with waterbirths (1%) than with births out of water (0.3%).
Why is this important?
The study provides reassurance about the safety of water births. Clinicians could discuss these findings with women considering using a birthing pool.
Women who received specialist care before giving birth were excluded from the main analysis, which reflects NHS care: women with identified problems during labour are referred to an obstetrician. The remaining women (giving birth in or out of water) are under midwifery care. When midwives identify problems during labour or close to birth, providing there is time to get out safely, women are advised to leave the water. Rates of midwife concerns were therefore higher among births out of water. Further analysis of births with no such concerns found no increase in complications with water births for women or their babies.
The researchers say that although umbilical cord snapping was more likely with waterbirths, the difference between groups was relatively small, and uncommon overall.
Previous studies have suggested that a randomised controlled trial comparing the safety of water births versus out of water births would not be possible. This study used a maternity care database and the researchers caution that data used from NHS maternity records could not be checked for accuracy. In addition, infant readmissions to hospital were not assessed because babies are often readmitted to children’s units rather than maternity units.
What’s next?
The researchers have informed NICE about their study and hope it will inform future guidance.
You may be interested to read
This is a summary of: Sanders J, and others. Maternal and neonatal outcomes among spontaneous vaginal births occurring in or out of water following intrapartum water immersion: The POOL cohort study. British Journal of Obstetrics and Gynaecology 2024; 129: 950 – 958.
A study of women’s views on water births: Milosevic S, and others. Factors influencing the use of birth pools in the United Kingdom: Perspectives of women, midwives and medical staff. Midwifery 2019; 79: 1 – 8.
A summary of the study’s main findings from Cardiff University.
Information about water births from the charity Tommy's and the National Childbirth Trust.
Information on taking part in NIHR research on pregnancy.
Funding: Health Technology Assessment Programme Commissioned Call, with support from Health and Care Research Wales.
Conflicts of Interest: None relevant.
Disclaimer: Summaries on NIHR Evidence are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that the views expressed are those of the author(s) and reviewer(s) at the time of publication. They do not necessarily reflect the views of the NHS, the NIHR or the Department of Health and Social Care.
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