Exploring the links between Zofran and Birth Defects

By Stuart Brown – 12th Oct 2015

Vomiting and nausea are two side effects of morning sickness that Zofran (ondansetron) has commonly been prescribed by Doctors to treat during pregnancy. This is despite the fact that it is only licensed by the FDA for use in cancer patients who are experiencing vomiting and nausea from cancer medications, surgery or chemotherapy.

This ‘off-label’ use of Zofran in the U.S to treat pregnant women was shown to have been encouraged by drug manufacturers GlaxoSmithKline who admitted guilt in 2012 and who have so far paid out $3 billion to the U.S Department of Justice as part of a wider settlement. Other individual lawsuits continue to be on going and are being actively pursued.

A December 2014 study from Sweden looked at 1349 infants who had been born between 1998 and 2012. It linked the drug to an increase in certain birth defects. Mothers had taken Zofran in early-pregnancy to treat morning sickness. The study concluded that taking Zofran during pregnancy raised the risk to the baby in two very specific ways:

  1. The increased risk of a cardiac septum defect (this is the dividing wall that separates the right and the left sides of the heart).
  2. A greater risk of a cardiovascular defect (this covers a wide variety of possible problems such as circulation issues and development abnormalities).

This was despite the study having made careful allowances for five common variables:

  1. If the mother smoked.
  2. The age of the mother.
  3. The weight of the mother both before and after the birth. (As measured by BMI – Body Mass Index)
  4. The year when the baby was delivered.
  5. The number of births after 20 weeks. (In other words to factor in when the mother gave birth).

Medical experts have also raised serious concerns about the use of Zofran (ondansetron) to treat nausea and vomiting in pregnant women. In an August 2014 article for The American Journal of Obstetrics and Gynecology, Dr. Gideon Koren highlighted that the number of off-label prescriptions for ondansetron had increased by over 100% in the United States between the beginning of 2008 and the end of 2013. From around 50,000 a month to 110,000.

The overall effect of this was that around 25% of the four-million pregnancies in the United States had used ondansetron (the generic form when Zofran came off patent in 2007) at some stage during their pregnancy in 2013.

He found this worrying having looked at data from two studies. The first from Denmark in August 2013 that looked at 897,018 pregnant women, and the second at the Sloan Epidemiology unit at the Center for Disease Control and Prevention which is ongoing with over 50,000 women having already been interviewed.

The Danish study showed:

“A 2-fold increased risk of cardiac malformations with ondansetron…leading to an overall 30% increased risk of major congenital malformations.”

The Sloane study showed:

“A 2-fold increased risk for cleft palate associated with ondansetron taken for NVP (nausea and vomiting) in the first trimester of pregnancy.”

Taken together these three studies do give significant cause for concern and any women who took ondansetron during their pregnancy should get in touch.