Ginger for Nausea in Pregnancy: Use Caution. (Good Efficacy, Lingering Safety Issues).

STANFORD, CALIF. -- Ginger for nausea and vomiting in pregnancy is an alternative therapy backed by reasonably persuasive evidence of efficacy, but unanswered safety questions dictate that it be used with caution, Dr. W LeRoy Heinrichs said at a conference on perinatal and pediatric nutrition.

The safety concern arises from the fact that ginger is found to be teratogenic on the Ames test. Ames testing assesses teratogenicity in bacteria, often using test compounds in extremely high concentrations; therefore, the results don't necessarily translate directly to humans. But it prompted Dr. Heinrichs and his coworkers to do a pilot study in which they placed ginger via feeding tube into the stomachs of pregnant rats. A high rate of miscarriage followed.

Once again, the clinical relevance is questionable. And while these are observations worth following up in human studies, realistically that's never going to happen.

"You'd have to do a study involving tens of thousands of pregnant women in order to find a 2%-3% malformation rate; it's just not going to be done," said Dr. Heinrichs, professor emeritus and past chair of gynecology and obstetrics at Stanford (Calif.) University.

As evidence of efficacy, he cited two published, well-conducted, randomized, double-blind, placebo-controlled trials involving a total of 100 pregnant women. In the more recent of the two studies, 70 women who were 17 weeks pregnant were randomized to 250 mg q.i.d. of powdered ginger or placebo in capsules for 4 days. Three women in the placebo group did not complete the trial. A key aspect of the study was that the investigators started with fresh ginger and then dried, powdered, and encapsulated it themselves.

"If you buy ginger in a health food store, you don't know what you're getting," the ob.gyn. observed at the meeting, which was jointly sponsored by Symposia Medicus and Stanford University.

After 4 days, the ginger group reported a significant decrease both in nausea and in the number of vomiting episodes, compared with the placebo group. The ginger group's overall symptom assessment was also ...