Medication Use During Pregnancy, With Particular Focus on Prescription Drugs: 1976–2008

Photo: Doctor talking to a woman about a prescription.

Researchers from Boston University’s Slone Epidemiology Center, in collaboration with researchers from the Centers for Disease Control and Prevention (CDC) and Harvard School of Public Health, have published a new study describing medication use during pregnancy in the United States during the period 1976–2008. You can read the abstract here.External The findings from this article are summarized in the following text.

Main findings from this study:

Data from the study showed that overall use of medications during pregnancy has increased during the last 30 years. During that time, the majority of pregnant women took at least one prescription medication during pregnancy. This study underscores the need for future research on the risks or safety of these medications during pregnancy.

Talk to Your Doctor

Pregnant women should not stop or start taking any type of medication that they need without first talking with a doctor. Women who are planning to become pregnant should discuss the need for any medication with their doctor before becoming pregnant and ensure they are taking only medications that are necessary.

  • During the first trimester of pregnancy
    • 70%–80% of women reported taking at least one medication and
    • By the end of the study period, about 50% of women reported taking at least one prescription medication.
  • Over the last 30 years
    • First trimester use of prescription medications increased by more than 60%;
    • Use of four or more medications during the first trimester tripled; and
    • Antidepressant use during the first trimester increased dramatically.
  • In addition, medication use during pregnancy
    • Increased with a woman’s age and education level,
    • Was higher among non-Hispanic White women than among women of other races or ethnicities that were studied, and
    • Varied by state of residence.

About medication use during pregnancy and this study:

Medication use during pregnancy is fairly common. Understanding the effects of specific medications used during pregnancy is important for both the mother and her baby. We know that taking certain medications, such as thalidomide or isotretinoin, during pregnancy can cause serious birth defects. Such medications should be avoided by all women who are or might become pregnant. While some medications are known to be harmful when taken during pregnancy, the safety of most medications taken by pregnant women has been difficult to determine. Better information on the safety or risks of specific medications will allow women and their doctors to make informed decisions about treatment during pregnancy.


For this study, researchers aimed to accomplish three goals:

  • Identify the number of women using any medication, including prescription and over-the-counter medications, during pregnancy
  • Learn about patterns and characteristics associated with use of specific medications taken during pregnancy, especially during the first trimester, which is an important time in pregnancy because the baby’s organs are developing
  • Understand how the use of specific medications has changed over time

To accomplish these goals, researchers analyzed data from the Slone Epidemiology Center Birth Defects Study from 1976-2008 to look at medication use over time and data from the National Birth Defects Prevention Study from 1997-2003 to look at characteristics of mothers who reported medication use during pregnancy.

Medication during pregnancy: CDC activities

About 1 in every 33 babies is born with a birth defect. Birth defects are one of the leading causes of infant deaths, accounting for more than 20% of all infant deaths. CDC is committed to working with its partners and the public to build a comprehensive approach to understanding and communicating the risks of birth defects that potentially are associated with the use of medications during pregnancy.

  • Research: CDC funds a large study of birth defects called the National Birth Defects Prevention StudyExternal. This study is working to identify risk factors for birth defects and to answer questions about some medications taken during pregnancy.
  • Technical expertise: CDC works with staff from the U.S. Food and Drug Administration and other professionals to help conduct studies on the effects of medication use during pregnancy and ways to prevent harmful effects.

More Information

To learn more about medication use during pregnancy, please visit:

For more information about birth defects, please visit:


Mitchell AA, Gilboa SM, Werler MM, Kelley KE, Louik C, Hernandez-Diaz S. Medication use during pregnancy, with particular focus on prescription drugs: 1976–2008. Am J Obstet Gynecol. 2011;204. [Epub ahead of print]

Page last reviewed: March 20, 2018