Objective: To evaluate the relief of pain in labour with subcutaneous and intracutaneous injections of sterile water, compared with placebo.
Design: Randomised controlled trial.
Setting: Labour ward with approximately 3000 deliveries annually in a suburban area near Gothenburg, Sweden.
Participants: Ninety-nine pregnant women at term, requiring pain relief for severe lower back pain during the first stage of labour. The women were randomised to receive four injections of 0.1 mL sterile water (without salt) intracutaneously (n = 33), four injections of 0.5 mL sterile water subcutaneously (n = 33) or placebo treatment (n = 33).
Main outcome measures: Reduction of labour pain measured by visual analogue scale.
Results: The median visual analogue scale pain score for labour pain was significantly lower compared with initial values in the two study groups and compared with placebo at 10 and 45 minutes after treatment. The median reductions in visual analogue scores after 10 minutes were 5.0 cm and 4.5 cm in the intracutaneous and subcutaneous injection groups, respectively; women in the placebo group scored a median reduction of 1.7 cm. After 45 minutes the median reductions in the visual analogue scores were 4.9 cm and 4.0 cm in the intracutaneous and subcutaneous injection groups, respectively, compared with 1.0 cm for women in the placebo group. No significant differences in analgesic effect or pain experienced during administration were found between the two study groups.
Conclusion: The new subcutaneous method of administering sterile water, as well as the earlier described intracutaneous injection method, were effective for the relief of pain in labour.