No longer 'midwifery voodoo': Sterile water injections effective for labour back pain

Getty Images/iStockphoto
Getty Images/iStockphoto 

The use of sterile water injections into the back to relieve severe labour pain has long been considered controversial and even labelled "midwifery voodoo". But, according to a new Australian study, it's a safe, simple and effective way to manage pain.

"Some midwives have used this practice in order to provide pain relief for a number of years, however until now, there has always been limited research to suggest that it works," Dr Nigel Lee of the University of Queensland tells Essential Baby, adding that it's been treated with skepticism both here in Australia and overseas.

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

As part of the study, published in The Lancet journal EClinicalMedicine, over one thousand women in labour with severe back pain were either given water injections or a placebo of saline solution. Data was collected from one British and 15 Australian maternity units over a five-year period between 2012 and 2017. 

And the results were clear: "Women were twice as likely to get relief from these injections than those who received the placebo," Dr Lee says. "Unlike normal labour pain, back labour pain is unpredictable and often continues between contractions with no break," he continues.

"Most drugs provided for labour pain are ineffective for back pain which may persist even after an epidural has been given. Water injections have been shown to be simple, effective and safe, and to have no effect on birth outcomes."

So why do the injections work so well?

According to Dr Lee there are nerve cells in the spinal cord that act like little gates. "They close to some pain and open to others based upon other stimulation that's going on," he says. "The injections cause a short, sharp pain for about 10 or 20 seconds and we think that basically opens the gate to that stimulus and closes the gate to the back pain. And that's why it works, almost instantly."

Dr Lee notes that women are usually given the injections during a contraction. "By the time the next contraction comes along in a couple of minutes the back pain has gone away or eased considerably."

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Co-author Professor Sue Kildea from Charles Darwin University adds that water injections will not only benefit women wanting to avoid pain relieving drugs during labour, but also "where women have little or no access to pain relief during childbirth, such as home birth and countries with developing health systems."

Midwifery Advisor Ruth King of the Australian College of Midwives tells Essential Baby, "It's wonderful to see that this practice, that midwives have known for many years works and provides acceptable options of care for women during labour, has been validated by an international study. We look forward to seeing a removal of previous barriers to midwives and health facilities implementing and offering this option to women as an element of care."

According to Ms King, sterile water injections provide women with the opportunity to continue to mobilise and follow their instincts in labour. "In this time of a heightened awareness of our health care system over-medicalising birth, this option in care supports women to retain their independence, mobility and control," she says.

 "The Australian College of Midwives is delighted to see research that validates the knowledge of midwives around sterile water injections and the opportunity they provide to women to remain mobile and in control of their labour and birth."