Skip Navigation U.S. Department of Health and Human Services
Agency for Healthcare Research Quality
Archive print banner

Pharmaceutical Research

This information is for reference purposes only. It was current when produced and may now be outdated. Archive material is no longer maintained, and some links may not work. Persons with disabilities having difficulty accessing this information should contact us at: Let us know the nature of the problem, the Web address of what you want, and your contact information.

Please go to for current information.

Study finds that some pregnant women are prescribed drugs that may be considered unsafe during pregnancy

Nearly half of pregnant women who receive medications other than vitamins may be taking drugs that the Food and Drug Administration classifies as having no human evidence of safety for use during pregnancy or that evidence has shown can harm a developing fetus. This findings is from a new study funded by the Agency for Healthcare Research and Quality (AHRQ grant HS10391) through the Centers for Education and Research on Therapeutics (CERTs) program.

The study, which is the largest to date to examine prescription drug use among women during pregnancy, was conducted by researchers at AHRQ's HMO Research Network CERT. The CERTs program is a national initiative to increase the awareness of the benefits and risks of new, existing, or combined uses of therapeutics and devices.

Researchers reviewed data from eight health maintenance organizations in diverse geographic areas. They evaluated prescription drug use by 152,531 women who delivered an infant in a hospital from January 1, 1996, through December 31, 2000, based on the FDA's risk classification system of drugs used during pregnancy. The study did not include a review of the use of over-the-counter medications or drugs prescribed in hospitals.

Researchers found that 64 percent of women were dispensed a medication other than a vitamin or mineral supplement within the 270 days prior to delivery. Of those, nearly 40 percent of women were dispensed a drug for which human safety has not been established (Category C on the FDA's list). Nearly 5 percent were dispensed drugs from Category D, which the FDA classifies as having positive evidence of fetal risk, but the benefits of use may be acceptable despite the risk. An additional 5 percent of women were dispensed a drug from Category X, for which the evidence indicates definite fetal risks based on human or animal studies or based on human experience, and the risk of using the drugs clearly outweighs any possible benefit.

The other approximately 50 percent of prescriptions were classified as Category A (risk to the fetus is remote) and Category B (animal studies do not show fetal risk and there are no controlled studies in women; or animal studies show risk, but controlled studies in women fail to show risk).

The researchers conclude that routine medication audits and physician education as well as new technologies—such as computerized prescription systems with clinical supports—may have the potential to reduce inappropriate prescribing for pregnant women.

For more information, see "Prescription drug use in pregnancy," by Susan A. Andrade, Sc.D., Jerry H. Gurwitz, M.D., Robert L. Davis, M.D., M.P.H., and others, in the August 2004 American Journal of Obstetrics and Gynecology 191, pp. 398-407.

Return to Contents
Proceed to Next Article

The information on this page is archived and provided for reference purposes only.


AHRQ Advancing Excellence in Health Care