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What to research before taking Zofran while pregnant

What is Zofran?

Zofran (also referred to as ondansetron) is an anti-nausea drug used to treat certain types of chemotherapy and radiation patients that experience nausea and vomiting after treatment. It is also used to treat patients that may be affected by the anesthesia medication from surgery.

While it has not been approved to treat women with moderate to severe morning sickness it has been prescribed “off-label” to pregnant women for morning sickness and severe hyperemesis gravidarum.

If you have been prescribed Zofran and you are pregnant you may want to research its uses and the claims of deformities caused by its use.


There have been no studies to verify its safety in pregnancy and several studies that indicate that the drug crosses the placenta in the first trimester such as this one (1) from the US national library of medicine. Another study included all women giving birth in Denmark between 1997 and 2010 (903,207 births) found the risk for major congenital heart defects(2) doubled with use of Zofran to treat nausea and vomiting during the first trimester. This same study states “Of the 1,248 women who filled a prescription for ondansetron during the first trimester, 4.7% (58) had a baby with a congenital malformation, compared with 3.5% (31,357) of those who were not exposed to ondansetron; this represented a 30% increased risk (adjusted odds ratio, 1.3).”

What types of congenital malformations are claimed?

Heart defects are among the most common claims against Zofran; these include

  • Heart Murmur: A clicking, whooshing, or other abnormal sound made by the heart, which is heard via a stethoscope exam. While some heart murmurs are minor issues, they can also be the first sign that a baby suffers from a serious heart defect,
  • Atrial Septal Defect: A hole in the wall between the atria, or upper chambers of the heart and
  • Ventricular Septal Defect: A hole in the wall between the lower chambers of the heart.

While heart defect are among the common claims against Zofran, there are other congenital malformations also attributed to it such as cleft lip and cleft palate, skull deformations, club foot, and more. Contact us for more information.


(1) Result Filters. (n.d.). Retrieved June 14, 2015, from

(2) (n.d.). Retrieved June 14, 2015, from

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