Zofran, also known by its trade name ondansetron, is a powerful anti-nausea medication that is approved for use in a few special settings. It is an extremely important drug in the modern world, and is even on the World Health Organization’s (WHO) list of essential medications. It was approved for use in 1991 by the FDA, and at the time was only permitted for patients suffering from chemotherapy-induced nausea. Before long, the FDA expanded its approval for use in patients recovering from radiation therapy and surgery. However, the drug’s manufacturer, GlaxoSmithKline, has aggressively pushed healthcare providers into prescribing it “off-label,” or in unapproved situations where the drug may be of some benefit. As a result, ondansetron has been given to many pregnant women to curtail nausea and vomiting during the first trimester. This appears to be a major risk, as several studies suggest a distinct link between birth defects and ondansetron use.


The research concerning ondansetron clearly demonstrates how medical data can be used to interpret just about anything. Fact is, there needs to be more research before any definitive statements can be made about the medication’s risks. There is conflicting data regarding whether the drug is dangerous or not for pregnant women. Evidence against the medication, though, is mounting, and it appears that at least one major study that concluded Zofran was safe appeared to be flawed methodologically.

That study was published in the New England Journal of Medicine, a prestigious medical research journal. The study reviewed 600,000 Danish births recorded by national registries, and it found no significant link between ondansetron and defects or stillbirth. However, another group of Danish researchers released a study the same day, using those same registries, and found that children exposed to ondansetron during development were twice as likely to develop heart defects.

What’s troubling is that Hong Kong researchers have proven conclusively that ondansetron readily passes through the placenta during pregnancy. Of the 41 fetal tissue samples those researchers studied, they found traces of ondansetron in all of them.

Furthermore, according to Canadian health oversight agencies, at least 10 newborns exposed to the drug have suffered from fetal growth restriction.

Is Zofran Safe During Pregnancy?

Even though Zofran is in Pregnancy Category B, which is reserved for drugs believed to be safe, doctors still must alert their patients to any possible risks or concerns with prescribed drugs. Some doctors fail to do this with medications that are still being researched. Failure to explain the risks of a drug is irresponsible and often negligent.

Also, GlaxoSmithKline has come under fire for its marketing of the medication. In 2012, the U.S. Department of Justice (DOJ) pursued a major claim against the pharmaceutical company for its unethical promotion of ondansetron in off-label applications. This includes promoting the medication for use in pregnant women. The DOJ’s case was strong enough to force GlaxoSmithKline to settle out of court for $3 billion.

As such, there is a precedent for claims against the company regarding ondansetron, so any parent whose child has been harmed by the medication should consider pursuing a claim of their own.