Effectiveness of Pharmacological Pain Relief Methods on Birth Experience: A Systematic Review and Meta-Analysis

The use of pharmacological pain relief methods during labour is increasing, however there is no clear evidence that pharmacological interventions can also improve women’s satisfaction with birth experience. To assess the effectiveness of pharmacological interventions on women's satisfaction with birth experience (primary outcome) and satisfaction with the received method (secondary outcome). We searched databases in English (MEDLINE, Cochrane Library, Embase, ProQuest, Scopus and Web of Science) and Persian languages (SID and Magiran) from inception until April 30, 2018 for clinical trials that pharmacological pain relief methods were compared with standard or routine cares, or non-pharmacological methods. The evaluation of studies in term of risk of bias was conducted using the Cochrane Handbook. Meta-analysis results were reported as OR and 95% confidence interval. In meta-analysis, subgroup analysis was performed based on the type of intervention. Due to the heterogeneity of over 30%, random effect was reported instead of the fixed effect. The heterogeneity was evaluated using I2, T2 and Chi2. The evaluation of the quality of the studies was also examined using the Grading of Recommendation, Assessment, Development and Evaluation Working Group (GRADE) approach. The results of 7 studies with low-quality in meta-analysis, showed that pharmacological methods significantly improved satisfaction with birth experience (OR = 2.99; 95% CI: 1.37 to 6.52; P = 0.006). However, meta-analysis of subgroups showed that only inhalation of Entonox gas (OR = 6.51; 95% CI: 3.47 to 12.22; P < 0.001), in contrast to epidural analgesia (OR = 1.19; 95% CI: 0.62 to 2.27; P = 0.60) and Hyoscine injection (OR = 2.58; 95% CI: 0.93 to 7.20; P = 0.07) significantly improved satisfaction with birth experience. Pharmacological interventions such as epidural, although introduced as one of the effective methods for pain relief, may not provide women with satisfaction with birth. However, more studies with precise methodology, high sample size, and standard tools should be performed to more accurately investigate the effect of pharmacological interventions on birth experience.