Taking Ondansetron During Pregnancy Does Not Appear to Increase Risk For Birth Defects

Woman sitting on bed feeling sick, while man sleeps

A study from the Slone Epidemiology Center at Boston University, in collaboration with the Centers for Disease Control and Prevention (CDC), found that taking ondansetron during early pregnancy did not appear to increase the chance of having a baby with a birth defect. Ondansetron (Zofran®) is a medicine used to treat nausea and vomiting that may be caused by surgery, chemotherapy, or radiation therapy. Healthcare professionals also prescribe ondansetron during pregnancy to reduce symptoms of nausea and vomiting, also known as “morning sickness.”

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Main Findings

  • In this study:
    • About 7 in 10 mothers reported “morning sickness” during the first three months of pregnancy.
    • Use of ondansetron by pregnant women increased from about 1 in 100 before 2000 to about 1 in 10 by 2011.
  • For most of the birth defects studied, researchers found that taking ondansetron during early pregnancy did not appear to increase the chance of having a baby with a birth defect.
  • Women should discuss options for managing nausea and vomiting symptoms during pregnancy with their healthcare providers.

About This Study

About Birth Defects

Birth defects are common, costly, and critical conditions that affect 1 in every 33 babies born in the United States. Birth defects are structural changes present at birth that can affect almost any part or parts of the body (such as the heart, brain, face, arms, and legs). They may affect how the body looks, works, or both.

Treating for Two: Safer Medication Use in Pregnancy

Our Work

CDC’s National Center on Birth Defects and Developmental Disabilities (NCBDDD) is working to improve the health of women and babies through its Treating for Two: Safer Medication Use in Pregnancy initiative. Treating for Two works to understand trends in medicine use among pregnant women and women of reproductive age, and provide women and healthcare providers with information about the safety or risk of using specific medicines during pregnancy. This information will allow women and their doctors to make informed treatment decisions about health conditions during pregnancy.

To learn more about our work in this area, visit the Treating for Two website.

More Information

Key Findings Reference

Parker SE, Van Bennekom C, Anderka M, & Mitchell AA. Ondansetron for Treatment of Nausea and Vomiting during Pregnancy and the Risk of Birth Defects. Obstetrics & Gynecology. 2018; 132 (2): 385-394.