Interventions for treating nausea and vomiting in pregnancy: a network meta-analysis and trial sequential analysis of randomized clinical trials

Introduction: Several drugs were explored for their utility in treating nausea and vomiting in pregnancy (NVP). The present study is a network meta-analysis of such drugs.

Methods: Electronic databases were searched for randomized clinical trials that have compared active interventions (with placebo or other active interventions) for treating NVP. Nausea scores were the primary outcome and changes in nausea scores, emetic episodes, adverse events, and vomiting control were the key secondary outcomes. Weighted mean difference was the effect estimate for continuous variable and odds ratio for the numerical variable. Random-effects model was used and the strength of the evidence was graded.

Results: Fifty studies were included in the systematic review and 42 in the meta-analysis. Acupuncture, chamomile, dimenhydrinate, doxylamine/vitamin B6, ginger, quince, metoclopramide, and vitamin B6 were associated with reduced nausea scores compared to placebo. Of these interventions, ginger and vitamin B6 were also associated with better vomiting control and less incidence of adverse events. Adequate evidence supporting the use exists only for ginger and the quality of evidence for this comparison is moderate. Strength of evidence for all other comparisons is very low.

Conclusion: Present evidence is conclusive on the therapeutic benefits of ginger in treating NVP. Although favorable results were obtained for several other interventions, the strength of evidence is very low. The results of this network meta-analysis should be interpreted with extreme caution as it might change with the advent of data from future head-to-head clinical trials.