RESUMO
To assess the efficacy and safety of ginger [rhizome of Zingiber officinale] to reduce severity of nausea and numbers of vomiting in early pregnancy. MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, CINAHL and SID databaseswere searched for relevant sources. Randomized trials of oral ginger in comparison with placebo for nausea and/or vomiting in early pregnancy were selected. Two reviewers assessed the trial quality and extracted the data independently. Five trials met the inclusion criteria to assess the efficacy. Based on these trials, there was a significant reduction in severity of nausea after taking ginger compared with placebo [Pooled SMD= 0.882, 90% confidence interval 0.267 to 1.496]. Also there was similar effect in reducing number of vomiting [Pooled SMD= 0.631, 90% confidence interval 0.433 to 0.829]. In addition, there were 5 trials or observational studies which had assessed the potential fetomaternal side effects of ginger. There was no supporting evidence for increasing pregnancy complications after using Ginger. Based on the current evidences, Ginger reduces the severity of nausea and frequency of vomiting in early pregnancy. There are considerations about adverse effects, but they are not supported by the clinical evidence. It seems that ginger could be used during pregnancy in therapeutic doses [almost 1 gr per day] for limited durations