Many women experience nausea and vomiting during pregnancy, and approximately 25 percent of employed pregnant women require time off from work because of these symptoms. Although many treatments have been proposed, concern regarding potential teratogenic effects have limited the use of medications. Herbal or “natural” remedies are perceived to be safe in pregnancy, but little is known about their effectiveness or potential adverse effects. Vutyavanich and colleagues studied the effectiveness of ginger on nausea and vomiting associated with pregnancy.

The authors studied women who attended a maternity clinic in Thailand before 17 weeks of gestation. Participants had significant nausea with no identifiable medical or pathologic cause. After completing an interview and a physical examination, patients were randomly assigned to receive either 250 mg of ginger or an identical placebo four times daily for four days. All patients were advised to have small, frequent, low-fat meals with increased carbohydrates and to avoid other medications. At follow-up after one week, pill counts were done to assess compliance. Both a visual analog scale and a Likert scale were used to assess the severity of nausea. Patients completed these scales before the study and then at noon and bedtime on each day of treatment. Patients also recorded any episodes of vomiting. Secondary outcomes included perinatal morbidity, fetal loss, preterm birth and congenital abnormality.

The 32 women assigned to ginger therapy were similar to the 35 women assigned to placebo in all relevant variables. All but two of the women in the study reported at least one episode of vomiting within the 24 hours before entering the study. Compliance rates were high. All of the ginger-treated patients and more than 85 percent of the placebo-treated patients took at least eight of the prescribed capsules.

Twenty-eight of the 32 ginger-treated patients had improvement in symptoms compared with only 10 of the 35 placebo-treated patients. Improvement was documented by both scales as well as subjective reporting of symptoms. The number of vomiting episodes significantly decreased in those treated with ginger compared with placebo-treated patients. Side effects were minor and occurred in both groups. No congenital anomalies were noted, more than 90 percent of deliveries were at term and all infants were discharged in good condition. One spontaneous abortion occurred in the ginger-treated group and three in the placebo-treated group.

The authors conclude that ginger effectively treats symptoms of pregnancy-associated nausea and vomiting with acceptable side effects and no evidence of adverse effect on pregnancy outcome.