Herbal remedies during pregnancy: are they safe and/or effective?

Robin Wulffson MD's picture
pregnancy, herbal products, effectiveness,  harm, birth defects, ginger

The prevalence of herbal medicine use during pregnancy is between 7% and 55%, depending upon the geographic area surveyed and the surveyed group's socio-cultural aspects and ethnicity. It is thought that the main reason women use these products during pregnancy is because they are fearful that pharmaceuticals available on the marketplace may be harmful or ineffective. However, herbal products can have adverse effects as well, and many of them are of no benefit. The medical literature contains studies evaluating herbal remedies in regard to possible benefit and harm. To date, only one herbal product, ginger, has been reported to be safe as well as beneficial to pregnant women. Ginger has been found to be just as effective as Dramamine for combating nausea and vomiting during pregnancy.

Many deem herbal products to be safe alternatives because “they are not really medicines.” That is a false assumption. Many prescription medications are derived from herbs. For example, digitalis and quinine, which are taken by heart patients, are herbal products. Furthermore, too low a dose could be ineffective, while too high a does could be fatal.

A study published in The Journal of Maternal-Fetal and Neonatal Medicine reviewed medical literature regarding the use of herbal remedies during pregnancy. The researchers identified more than 500 studies; however, many of them had design flaws and other problems. They ultimately identified 14 randomized, controlled trials, which they deemed suitable for inclusion in their evaluation. They found that ginger was the most thoroughly studied remedy, and the one found most consistently effective. It relieved nausea and vomiting associated with pregnancy (morning sickness) better than a placebo, and was as good as Dramamine at doing so.

They found no evidence for any benefit from other popular herbal products. Cranberry juice, which is often used to prevent or treat bladder infections, was found to be ineffective. Preeclampsia, or toxemia of pregnancy, is a complication of pregnancy that can progress to eclampsia, manifested by seizures. Some women take garlic as a preventative for preeclampsia; however, it has no known benefit. The study also found that raspberry leaf does not shorten labor and that castor oil has no effect on inducing labor.


Researchers at the Centers for Disease Control and Prevention (CDC) estimated the prevalence and patterns of herbal use among U.S. women immediately before and during pregnancy. Their analysis involved10 centers across the nation with a total of 4,239 women who did not deliver a child with a major birth defect. A computer-assisted telephone interview was used to collect data from mothers about exposures in the three months before pregnancy and throughout pregnancy to delivery. The researchers found that 462 mothers (10.9%) reported use of an herbal product during that period of time. Use of herbal products was highest during the first trimester (first three months). The use of herbal products increased with age, with a higher prevalence associated with age older than 30 years. Herbal use was also highest among women with more than a high school education and those with a household income of $20,000 or more per year. The most commonly used herbals early in pregnancy were ginger (ginger is believed to prevent nausea and vomiting), and ephedra, the authors report. Later in pregnancy, herbal teas and chamomile were most commonly used. Other commonly used herbals were cranberry extract, raspberry leaf, mint or peppermint, and primrose oil.

The authors expressed concern that use of herbal products was highest during the first trimester because this is a critical period of fetal organ development. They noted that the U.S. Food and Drug Administration (FDA) withdrew ephedra from the market in April 2004 because of concerns about cardiovascular effects such as increased blood pressure and irregular heart rhythm; these effects could be harmful to the developing fetus. The authors reported that knowledge of the effects of herbal products on the developing fetus is “remarkably limited.” They added that it is difficult to ascertain the ingredients in herbal products with any degree of reliability because of the nature of the herbal product industry, which may label ingredients inaccurately or change the blend of their ingredients. Furthermore, despite their widespread use, many pregnant women who use herbals do not tell their physicians.

The authors concluded that it is critical that risks and relative safety of herbal products in pregnancy be studied and that more data on the fetal risks associated with these products be accumulated. They recommended that, until such studies were completed, healthcare providers should ask their patients about their use of herbals “in a routine and nonjudgmental fashion,” and should inform their patients that the fact that a substance is natural does not necessarily mean that it is safe for the fetus. The stated, “Providers also should inform patients that it would be prudent to err on the side of caution regarding use of these products during and surrounding pregnancy, because little is known about their potential risks.”

Journal of population therapeutics and clinical pharmacology

See also:
Princess Kate’s hospitalization for severe nausea and vomiting might be due to twins
25 Reasons People Take Dietary Supplements Even if Proven Worthless