Sterile water injection for labour pain: a systematic review and meta‐analysis of randomised controlled trials

BACKGROUND: Up to one-third of labouring women will experience painful 'back labour'. Sterile water injected lateral to the lumbosacral spine is a simple and well-researched approach to this pain. OBJECTIVE: To determine if sterile water injection for low back pain compared to placebo or alternative therapy increased or decreased the rate of Caesarean section. SEARCH STRATEGY: We performed a literature search with no language restriction in four databases: the Cochrane library, EMBASE (1980-2009), Ovid Medline (1950-2009) and CINAHL (1982-2009). SELECTION CRITERIA: We included all randomised controlled trials (RCTs) of sterile water injection for labour pain that included outcomes of interest and original data. DATA COLLECTION AND ANALYSIS: We compared Caesarean section rates among women who received sterile water injection in labour with those who received either placebo treatment or another non-pharmacological treatment modality. Other outcomes included pain scores, use of regional analgesia and women's assessment of treatment. We used Revman 5 for the meta-analysis. Data were entered by one reviewer and independently cross-checked. Pooled outcomes were reported as Relative Risk (RR) or Weighted Mean Difference using Mantel-Haenszel fixed-effects model except when the I2 value >50% indicated significant heterogeneity in which case random-effects model was used. MAIN RESULTS: We included eight RCTs. The Caesarean section rate was 4.6% in the sterile water injection group and 9.9% in the comparison group (n = 828) (RR 0.51, 95% CI: 0.30, 0.87). CONCLUSION: We believe that a large RCT should be mounted to validate our findings regarding the impact of sterile water injections on mode of delivery.