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Water injections shown to relieve back pain in labour


Sterile water injections have been shown to provide effective pain-relief for women with persistent lower back pain in labour, according to Oxford researchers.

The ICARIS trial, published in The Lancet journal EClinicalMedicine, was a collaboration between Oxford University Hospitals (OUH) NHS Foundation Trust, the University of Oxford and the University of Queensland, Australia.

The research team says that their research proves that water injections are simple, effective and safe, and have no effect on birth outcomes.

Prof. Sally Collins, OUH Consultant Obstetrician and Associate Professor in the Nuffield Department of Women's and Reproductive Health, who led the UK part of the study, said: "Although many other countries were already using this simple pain-relieving technique, the evidence it works was sadly lacking so many healthcare professionals dismissed it as nonsense. The NICE guidelines even go as far as to say it shouldn't be used.

"This robust trial provides much needed evidence that it works using the strongest possible research method, a randomised, double-blind, placebo-controlled trial. The fact that it is cheap, simple and needs minimal training should mean it will be able to provide pain-relief for women in developing countries where access to other pain-relief may be limited," said Prof Collins, senior author of the previous Cochrane review of the technique.

More than 1,000 women with severe back pain took part in the trial between 2012 and 2017 at Oxford's John Radcliffe Hospital and 15 Australian maternity units. They were randomised to either subcutaneous water injections or a placebo of saline solution.

Compared to the placebo, twice as many women who received the water injections reported that their pain was reduced by at least half and the effect lasted for 90 minutes and longer.

Wendy Randall, OUH Consultant Midwife, added "We are so proud to have been part of the largest multi-centred, international, midwifery-led trial. This trial has huge implications and will hopefully improve the experience for women in labour in any birth setting in the UK and worldwide. It is especially beneficial for women who choose to birth at home or in midwifery-led units where epidurals are unavailable.

"We would like to thank all the women who consented to participate in this trial, especially the 250 women in Oxford. Without them, this would not have been possible."

The lead researcher on the study, Dr Nigel Lee of the University of Queensland (UQ) School of Nursing, Midwifery and Social Work, said the injections were previously seen as controversial but have now been shown to be safe and effective.

"To provide pain relief, midwives inject small amounts of sterile water into the skin of the lower back of women in labour who have persistent back pain," he explained. "This practice has been going on for a number of years with limited research to suggest that it works. In fact, many hospitals refused to support the procedure, viewing it as 'midwifery voodoo'.

"This research provides definitive evidence that water injections offer effective pain relief for the majority of women with labour back pain.

"The implications of the results of our trial are huge; unlike normal labour pain, back labour pain is unpredictable and often continues between contractions with no break. Most drugs provided for labour pain are ineffective for this constant back pain which may lead some women to having an epidural when they would have preferred not to have one."

In addition to OUH, the University of Oxford and UQ, the collaboration included Australia's Charles Darwin University and the University of Skövde, in Sweden.