Zofran, an anti-nausea drug commonly prescribed “off-label” to pregnant women with morning sickness, has been linked to an increased risk of heart defects, cleft lip, cleft palate, and other devastating birth defects.

What is Zofran?

Zofran is a member of a class of medications known as 5-HT3 receptor antagonists. These drugs work by reducing the effects of the serotonin in the body. Serotonin is a chemical naturally produced by the human body that is known to cause nausea and ultimately vomiting. Zofran and other 5-HT3 receptor antagonists basically interrupt the serotonin messages sent from the brain to the rest of the body that it should feel nauseous and get ready to vomit.

Zofran has been on the market for more than 20 years. It was originally approved for use in the United States by the U.S. Food and Drug Administration (FDA) in 1992, although it was mainly used by cancer victims at the time. Recently Zofran’s manufacturer GlaxoSmithKline (or GSK) found a new market for this nausea medication, that market being pregnant women. The pharmaceutical company saw a potential to create a new revenue stream that could generate millions of dollars in revenue for GSK by marketing Zofran to pregnant women who were experiencing morning sickness and nausea. However, it has recently been alleged that use of Zofran during pregnancy may increase the risk of birth defects. 

Zofran Pregnancy Studies

In February 2013, a study published in the New England Journal of Medicine found no association between Zofran and birth defects; however, other studies dispute these research results.

The objecting researchers’ conclusions were based on data from a Danish registry, comparing outcomes among nearly 2,000 women who took Zofran during pregnancy between 2004-2011. The average gestational age of exposure was 10 weeks, so half the women who took Zofran started treatment after their baby was no longer at risk of major birth defects.

In August 2013, a different group of researchers looked at the same Danish registry data, but with more pregnancies (nearly 900,000) and over a longer period of time (1997-2010). They found that Zofran was associated with a doubled risk of heart defects, leading to a 30 percent increased risk of birth defects overall. Of the 1,248 women who used Zofran during the first trimester, 4.7 percent had a baby with a birth defect, compared to 3.5 percent of women who did not use Zofran.

Despite these findings, the U.S. Food and Drug Administration recently rejected a petition to change Zofran’s drug category, saying in an October 2015 statement that these studies “do not support a determination that there is an increased risk of fetal adverse outcomes.”

Zofran And Pregnancy Risk

Zofran is not approved for use during pregnancy but is frequently used off-label to treat morning sickness. The FDA classifies Zofran as a “Pregnancy Category B” medication, meaning animal studies have not found evidence of birth defect risks, but no one knows for sure if the anti-nausea drug is safe. Though new research is still uncertain of the timing and dosage that may increase or decrease the risk of birth defects for mothers taking Zofran, one thing is clear. There is a distinct possibility of newborns being born with cleft palates or cleft lip and three types of heart defects, including ASD (Atrial Septal Defect), VSD (Ventricular Septal Defect), and heart murmur, when a pregnant woman ingests Zofran.

It’s important to note that despite its potential risks, the FDA has not stopped Zofran from being prescribed. However, doctors have the legal duty to inform all pregnant women of the risks associated with Zofran prior to prescribing it. This may stem from the fact that Zofran isn’t created specifically for nausea and vomiting. Its main function is to treat those with cancer, as surgery, chemotherapy, and radiation can often cause nausea. Despite this fact, doctors are still legally allowed to prescribe the medication how they wish, even for “off-label” (or non-FDA approved) uses.

The most common types of birth defects that can potentially come from Zofran include:

• Musculoskeletal anomalies
• Mouth deformities
• Jaundice
• Heart defects

Zofran Lawsuits

Although some pregnant women have found that Zofran eases their nausea and vomiting significantly, others have filed Zofran birth defect lawsuits against its maker, GlaxoSmithKline. In fact, the Zofran lawsuits are not limited to mothers who once took the medication.

In 2012, GSK settled a federal, civil false claim lawsuit alleging GSK had promoted Zofran for the treatment of morning sickness in pregnant women despite being approved only for post-operative nausea, and that GSK had paid doctors kickbacks for prescribing Zofran. In 2012, GSK settled that lawsuit along with three similar lawsuits regarding other GSK products for $1.043 billion.