Sterile Water Injections – Taking the Pain Out of Back Labour

Sterile Water Injections – Taking the Pain Out of Back Labour

Sterile water injections used for labouring women describes the injection of minute amounts of sterile water into the skin. The injections are fairly new to be used during labour but have shown such wonderful results, so we interviewed the amazing Carolyn Hastie, who previously managed Belmont Birthing Service and was NSW Midwife of the Year, to find out more.

Are Sterile Water Injections Really Just Injections With Water In Them?

Yes, it is really just water!

How Did It All Come About To Use Water In This Way?

From my understanding, the water injections being used for labouring women came from their usage with people with renal colic/kidney stones. They are very effective for that condition.

The concept behind the development of sterile water injections for pain is ‘gate control theory’. The skin has thousands of receptor sites and nerve cell endings which scan for pain, pressure, touch etc., and transmit that information to the brain very, very quickly. The sensations shoot up the nerves and spinal cord to the brain. The sensations (which are chemical and electrical signals) go through little traffic control stations.

The signal boxes in the nerve pathways are ‘manned’ by chemical signalers which let pain, pressure, touch etc., signals through to the brain. The signal boxes in the nerve pathways are called ‘gates’. They are called gates because they choose which signal to let through. When the brain receives the signals, it decides what action to take.

The traffic controllers (chemicals) which man the ‘gates’ preference skin signals over internal signals because the skin is monitoring the outside environment and lets the brain know when there is immediate danger. When a woman has back pain in labour, the pain signals are slow, internally generated signals. Some back pain is normal when the baby’s head is decending in the pelvis, it presses on the sacrum, pushing it out as the head turns on its way down. That is nature’s signal to the mother than the birth of her baby is imminent. When a woman has intractable back pain, because of the baby being in the posterior position, then the water injections may be useful. If a woman has the water injections into her skin, it stings for about thirty seconds. That sting switches on the fast fibres. The fast fibre signals from the skin come racing up to the gate, the traffic controlling chemicals recognise an immediate threat, close the gate to the slow pain messages and let the quick skin related message through. The internal pain signal is stopped in its tracks and the woman no longer feels that internal sensation. That effect lasts for about 90 minutes.

How Effective Are Sterile Water Injections?

They are very effective for the majority of women. The pain level of the back pain has to be a high enough level so that the wasp like sting is worth it. On a 0-10 score, with 10 being the worst pain imaginable, the pain level has to be about an 8 or above.

How Many Women Have You Witnessed Having The Injections?

I’ve seen lots of women have the injections and only one has said it wasn’t worth it. Her pain scale was not high enough when the midwives administered the injections.

How Quickly Does It Work and How Much Pain Does It Take Away?

It works immediately and takes away the internal pain.

Do Sterile Water Injections Work For Everyone?

Even the woman who said it wasn’t worth it pushed her baby out very quickly after the injections when she was not pushing effectively before the injections, because of the pain in her back.

When Is The Best Time To Have Sterile Water Injections During Labour?

They are best used when the woman’s backache is 8 out of 10 and she can’t manage it.

What Would You Suggest To A Woman Who Is Interested In Having Sterile Water Injections In Labour?

Women could certainly ask their local service (hospital/midwives) about the use of these injections for back pain. Janice deoCampo from Colac teaches how to do these injections and has run workshops on using them. Janice brought the idea to Australia after her daughter used them in labour in Sweden. Janice ran a workshop for us at Belmont Birthing Service and our midwives use them when necessary. These injections are also being used at John Hunter Hospital. We wrote a policy and put the process through the Clinical Governance Unit for approval.

What Do You Think About Sterile Water Injections?

These injections are fantastic. Quick, easy and safe. Women are able to stay mobile and there are no other effects from them. Obviously, infection could be a risk, if sensible normal procedures were not followed. We have actually used them for suprapubic pain (referred sensation from the cervix opening, felt just above the pubic bone). This pain is another one of those indicators from nature telling the woman that labour is progressing, but for an occasional woman, she is not able to bear it. We have found the sterile water injections work well there too – the system works all over the body because of the ‘gates’.

If the labour is a long one, the woman may need a couple of ‘doses’, but for many women, the relief of the internal pain enables her to relax, the pelvic muscles relax, the baby turns, the cervix dilates and out it comes! In second stage it can be amazingly fast. In first stage it depends on how open the cervix already is when the injections are given as to how fast it goes.

Comments About Sterile Water Injections From Other Midwives

“I have only used this once with rather miraculous results, so not really qualified to comment. Went from back pain scale 9&1/2 to zero in 2 contractions!” — Di

“I have used water injections for back pain in labour for the last 3 years in 2 different hospitals, always with amazing results. Very few women say it didn’t help at all.” — Sally

Pointers For Midwives/Doctors Interested In Doing Sterile Water Injections For Labouring Women

a) Use fine needles 25gauge
b) Use 0.1mL of sterile water (yes, that’s all)
c) Get the woman to point to where the pain is worst, inject her there
d) Two midwives administer the water at the same time – the sting may stop the woman from having the other side done if only one midwife does it.
e) Have the partner hold the woman’s hands and talk her through the injections as she can automatically swipe at you when you give the injections
f) Administer the water injections into the skin, it’s intra – dermal, not sub cutaneous, not under the skin, the idea is to raise a little bleb which stretches the skin and sets off the receptors
g) Leave the area alone! the sting is the thing, if you rub it, it will lose its effectiveness.
h) The Swedish midwives give four injections, either as four in a row across the back, or on the four points of an inverted trapezpoid shape on the woman’s sacrum.

Further Information

Read this PDF on a sterile water project with contact details for Janice HERE. Midwives if your hospital does not provide this service, let your workplace know so you can organise some training!

Last Updated: February 23, 2015


Kelly Winder is the creator of, a doula, writer and mother to three awesome children.Currently she's travelling the world for 12 months with her partner and children, and hopes to inspire more families to do the same.

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