Zofran for morning sickness: The risks are minimal

Dr. Horsager talking with patient about Zofran®
Dr. Horsager has been getting more questions about ondansetron (also known as Zofran®).

Last week, I had a patient who was really worked up during her ultrasound. At the end of the test, she asked me, “Does everything look OK?” I reassured her that everything looked as normal as it possibly could. But she seemed more anxious than usual.

When I asked her why, she said she’d seen a law firm’s commercial about birth defects and ondansetron (also known as Zofran®). She was upset because she had taken the medication for morning sickness – nausea and vomiting during pregnancy – and she was afraid the drug had harmed her baby.

Morning sickness can usually be managed with simple dietary changes. Sometimes, though, symptoms don’t go away with dietary changes alone. Doctors prescribe medications like ondansetron so you won’t get dehydrated or lose weight because of persistent morning sickness symptoms – which could cause a whole host of problems for you and your baby.

Is ondansetron safe?

Ondansetron was originally used to treat nausea associated with chemotherapy or surgery. In the United States, it rapidly became the most frequently prescribed drug for morning sickness. Estimates suggest one out of every four pregnant women receive a prescription for ondansetron.

Definitive studies evaluating the safety of medications, especially during pregnancy, are difficult to find. For ondansetron, physicians have relied on two imperfect methods of study. One method involves looking at registries of children born with birth defects and asking their mothers what medications they remember taking during their pregnancy. The other involves comparing outcomes in children whose mothers received prescriptions for ondansetron to those who received a prescription for another nausea medication. Clearly, neither method is sufficient to give us all the answers we need.

Original work suggested no increase in birth defects in women who took ondansetron early in pregnancy. However, more recent studies have raised concern over the possibility of a doubling in risk of cleft palate and heart defects in newborns exposed to ondansetron during pregnancy.

It’s important to note that another study using similar information did not show the same increased risk for birth defects. Until we have better information about the true risks, ondansetron should be tried only after other therapies have failed.

What are alternative nausea remedies?

I always advise women suffering from morning sickness to start with dietary changes and eliminate “triggers” that cause or worsen symptoms. Ninety percent of pregnant women with morning sickness symptoms see improvement just by altering their diets.

If that doesn’t work for you, there are two other methods I frequently suggest before prescribing ondansetron:

  • Ginger: Formulations that contain ginger can help reduce symptoms.
  • Vitamin B6 and doxylamine: A safe medication, made from these two ingredients, is approved to treat morning sickness symptoms.

However, if you have severe nausea and vomiting that does not improve with these methods or other nausea medication, your doctor may prescribe ondansetron. The medication can keep you from losing weight or becoming dehydrated, which can harm you and your baby.

If you are pregnant and have taken ondansetron or Zofran® during pregnancy, I want to reassure you that it likely has not affected your baby. Even if the increased risk for cleft palate or heart defects turns out to be true, the risk to your baby is still very, very small.

As always, I encourage you to ask questions. Talk to your doctor if you have concerns about taking ondansetron or Zofran®.

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