Table 2

Pooled estimates of effect size (95% confidence intervals) expressed as weighted relative risk for adverse events and side-effects of ginger versus control group (Placebo, Vitamin B6, Dimenhydrinate)
Outcome Number of studies RR 95% CI Heterogeneity
Chi2 I2 (%)
Ginger versus placebo
#Allergic reaction [30] 1 3.00 0.12 to 72.20
#Dehydration [30] 1 3.00 0.12 to 72.20
#Spontaneous abortions [29,30] 2 3.14 0.65 to 15.11 0.00 0
Abdominal discomfort [29] 1 3.27 0.14 to 77.57
Diarrhea [29] 1 3.27 0.14 to 77.57
Drowsiness [29] 1 2.82 0.12 to 66.62
Headache [29] 1 1.31 0.44 to 3.89
Heartburn[19,29,30] 3 5.03 0.89 to 28.61 0.35 0
Worsening of symptoms requiring pharmaceutical treatment [30] 1 0.33 0.01 to 8.02
Ginger versus vitamin B6
#Arrhythmia [20] 1 0.51 0.05 to 5.46
#Spontaneous abortions [21,27] 2 0.49 0.17 to 1.42 1.67 40
Belching [27] 1 27.18 1.63 to 453.06*
Burning sensation after capsule ingestion [27] 1 1.01 0.21 to 4.91
Drowsiness [20,28] 2 0.75 0.48 to 1.19 0.18 0
Dry retching [27] 1 0.93 0.76 to 1.15
Heartburn [20,28] 2 2.35 0.93 to 5.93 1.03 3
Vomiting [27] 1 1.51 0.26 to 8.91
Ginger versus Dimenhydrinate
Drowsiness [26] 1 0.08 0.03 to 0.18**
Heartburn [26] 1 1.44 0.65 to 3.20

#Major adverse events (serious complications, possibly detrimental to the mother or fetus) (authors’ judgement); rest considered minor (discomfort, but manageable side effects) - sorted alphabetically, first major then minor events.

*Indicates significant finding: Ginger significantly increased the risk of belching compared to vitamin B6.

**Indicates significant finding: Dimenhydrinate significantly increased the risk of drowsiness compared to ginger.

RR, Relative risk; CI, confidence interval.

Viljoen et al.

Viljoen et al. Nutrition Journal 2014 13:20   doi:10.1186/1475-2891-13-20

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