Widespread use of medications among pregnant women, researchers report

Although a number of antenatal medication exposures are known to cause birth defects, there is insufficient information on the risks and safety for the vast majority of medications, whether they are obtained by prescription or over-the-counter (OTC). As a result, pregnant women may unknowingly take a medication that poses risk to their fetus; on the other hand, anxiety about the potential harmful effects to the fetus may discourage women from adhering to beneficial treatments.

The findings came from data collected by the Slone Epidemiology Center's Birth Defects Study (1976-2008) and the CDC's National Birth Defects Prevention Study (1997-2003), which together interviewed more than 30,000 women about their medication use during pregnancy. The results included information not only on use of prescription drugs but also OTC medications, which are more commonly used and are not typically recorded in electronic medical/insurance records.

The following is an outline of the study's findings:

1. During the first trimester of pregnancy
   • 70-80 percent of women reported taking at least one medication; and
   • By 2008, about 50 percent of women reported taking at least one prescription medication.
2. Over the last 30 years
   • First trimester use of prescription medications increased by more than 60 percent;
   • Use of 4 or more medications during the first trimester tripled; and
   • Antidepressant use during the first trimester increased dramatically.
3. In addition, this study reported that
   • Medication use increased with a woman's age and education level;
   • Use was higher among non-Hispanic white women compared with women of other races or ethnicities that were studied; and
   • Use during pregnancy varied by state of residence.

According to the researchers, defining research priorities requires an understanding of patterns and factors associated with actual use of the wide range of specific medications that are taken during pregnancy and particularly during the first trimester, when concerns about development of birth defects are greatest. "These data identify prescription medications that are currently most commonly used and therefore urgently require research on their risks and safety; they also reinforce the need for ongoing surveillance regarding medication use in pregnancy and its consequences," said lead author Allen A. Mitchell, MD, director of BU's Slone Epidemiology Center. "Not only is it critical to identify how many OTC and prescription medications are taken by pregnant women and what those specific medications are, but it is also important to know how use of medications changes over time," he added.

This study was supported in part by a Cooperative Agreement with the Centers for Disease Control and Prevention through the Massachusetts Department of Public Health, cooperative agreements from the Centers for Disease Control and Prevention to the centers participating in the National Birth Defects Prevention Study, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development.