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Sterile water injections for relief of back pain in labour

What are sterile injections?

Many women will experience back pain in labour. Often referred to as ‘back labour’, the pain can continue between contractions and be severe enough to influence plans and decisions about pain relief.

Sterile water injections (SWI) are an effective method for the relief of back pain in labour. The procedure involves a small amount of sterile water (0.1mL to 0.2 mL) injected under the skin at four locations on the lower back (sacrum).

How does this work?

The injections cause a brief but intense stinging sensation, like a wasp sting, that lasts for about 30 seconds and then wears off completely. As the stinging sensation eases, relief from the back pain is felt.

To distract from the stinging sensation the injections are done during a contraction by two midwives at the same time. Women benefit from support and encouragement as the injections are being given.

How long will the pain relief effect last?

SWI provides effective pain relief for up to 85 per cent of women with back pain in labour and the effect can last for up to two hours.

Advantages of SWI

  • Often immediate effect.
  • No effect on mother's state of consciousness.
  • No effect on baby.
  • Does not limit mobility.
  • Does not adversely affect labour progress.
  • A simple procedure that can be administered by your midwife.
  • Can be repeated as needed.

Will SWI help my labour pain?

Sterile water injections are an excellent alternative for relief of back pain in labour. Though SWI will not provide pain relief from contraction pain, once the back pain is eased, you may cope better with labour pain. As the back and pelvic muscles relax following the relief of pain, this may assist with the progress of your labour.

As sterile water is not a drug and there are no known side effects for mother or baby, SWI may become the preferred choice for the relief of back pain in labour for many women.


  1. Fogarty, V. Intradermal sterile water injections for the relief of low back pain in labour: A systematic review of the literature. (2008) Women and Birth; 21: 157-163
  2. Hutton EK, Kasperink M, Rutten M, Eitsma A, Wainman B (2009) Sterile water injection for labour pain: a systematic review and meta-analysis of randomised controlled trials. British Journal of Obstetrics and Gynecology (Published Online: 14 May, 2009).
  3. Lee N, Webster J, Beckmann M, Gibbons K, Smith T, Stapleton H, Kildea S. Comparison of a single vs. a four intradermal sterile water injection for relief of lower back pain for women in labour: a randomised controlled trial. Midwifery. 2013 Jun 1;29(6):585-91.
  4. Lee N, Martensson LB, Kildea S. Cross sectional study of Australian midwives knowledge and use of sterile water injections for pain relief in labour. Women and birth. 2012 Dec 1;25(4):e74-9.
  5. Lee N, Kildea S, Stapleton H. “No pain, no gain”: The experience of women using sterile water injections. Women and Birth. 2017 Apr 1;30(2):153-8.
Mater acknowledges consumer consultation in the development of this patient information.
Mater Doc Num: PI-CLN-430055
Last modified 05/6/2020.
Consumers were consulted in the development of this patient information.
Last consumer engagement date: 04/6/2020
For further translated health information, you can visit healthtranslations.vic.gov.au/ supported by the Victorian Department of Health and Human Services that offers a range of patient information in multiple languages.
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