Sterile Water Injections — Evidence Library

What it is

Four small intradermal or subcutaneous injections of sterile water (0.1–0.5 mL each) are placed over the sacrum. The mechanism is thought to be counter-irritation and gate-control of pain signals. It doesn't help contraction pain but can dramatically reduce back-labor pain, and can be repeated as needed.

Evidence review links

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Cochrane: Intracutaneous or subcutaneous sterile water injection for relieving pain in labourCochrane

Possible benefits

Marked relief of back labor for many peopleReview sources ↓
No effect on the baby or on the ability to move, eat, or use waterReview sources ↓
Can be given by a nurse or midwife; no anesthesiologist neededReview sources ↓

Possible risks

Injection stings intensely for 20–30 seconds — often described as worse than a contraction brieflyReview sources ↓
Only helps back pain, not overall contraction painReview sources ↓

Alternatives

Counterpressure and hip squeezesReview sources ↓
Hydrotherapy and TENSReview sources ↓
EpiduralReview sources ↓

Current evidence

Cochrane 2012 and multiple RCTs show significant reduction in back-labor pain with sterile water injections; no adverse maternal or fetal outcomes.

Where the evidence is clear · where people may choose differently

For most topics, guidelines from ACOG, WHO, and other major bodies broadly agree on the core safety points (when to act in an emergency, informed-consent standards, monitoring baselines). Where reasonable people — and even guidelines — differ tends to be around thresholds (when to start or stop something), preferences (comfort, environment, support), and values (how you weigh small risks against benefits). Use the questions below to explore those pieces with your care team.

Educational only. Your care team can help you weigh what applies to your specific situation.