Pregnant Woman Looking At Belly
08 September 2016

Does Zofran Cause Birth Defects?

Recent studies have challenged the safety of Zofran, a pharmaceutical frequently prescribed during pregnancy – linking the drug to an increased risk for serious birth defects. While Zofran is an effective treatment for nausea and vomiting, new research suggests that the drug may come with severe side effects for mothers and unborn children alike.

Zofran For Morning Sickness: Is The Drug Safe?

Most pregnant women will experience morning sickness, usually during the first trimester of pregnancy. Nausea, vomiting and splitting headaches are unfortunate, but almost unavoidable, side effects of being pregnant.

While some women find relief through moderate lifestyle changes, and others swear by benign nausea suppressants like ginger and lemon, severe cases of morning sickness can be surprisingly dangerous – for both mothers and children.

In increasing numbers, obstetricians and other physicians have turned to a drug called Zofran in an attempt to alleviate their patients’ symptoms.

What Is Zofran Used For?

Zofran is a potent anti-nausea drug, designed to treat the most severe forms of nausea and vomiting imaginable. Ondansetron, Zofran’s active ingredient, is approved to treat patients undergoing cancer treatments, like chemotherapy and radiation, along with people who get sick after receiving surgical anesthesia. But like most pharmaceuticals, the drug’s safety was never even studied in pregnant women.

Morning sickness isn’t usually a dangerous pregnancy complication, but for obvious reasons, no one wants to feel nauseous all the time. Finding an effective remedy for morning sickness, however, has been difficult. Home remedies – like eating small meals throughout the day or spiking your water with a hit of lemon juice – don’t work for everyone. Pharmaceutical drugs, for that matter, are rarely tested in pregnant women, who are approached with understandable caution in scientific research.

Pregnant Woman

Between 1956 and 1983, pregnant women were usually prescribed a drug called Bendectin, a simple combination of Vitamin B6 and doxylamine, an antihistamine. But Bendectin was quickly pulled from the market, after several scientific studies linked the drug to an increased risk for birth defects. That left a huge gap in the market. Many women wanted an aggressive treatment for moderate to severe cases of morning sickness, but just couldn’t find one. A drug called Zofran soon filled the gap.

Can Zofran Cause Birth Defects?

Today, Zofran has become the most common pharmaceutical treatment for morning sickness in the world, according to Medscape Pharmacists. And early studies seemed to support the drug’s use. In 2004, for example, a small study on 352 pregnant women found no evidence that ondansetron could cause birth defects in newborns. But in looking at larger groups of patients, more recent research has found troubling signs that Zofran may not be as safe as we once believed.

Using data from more than 9,000 pregnancies, researchers at Harvard University found that women who took Zofran were more than twice as likely to deliver children with a cleft palate – an oral abnormality that can make feeding, speech and hearing difficult for children. Several extremely large studies conducting in Denmark and Sweden have discovered compelling evidence that Zofran – when taken during the first trimester – poses a risk to an unborn child’s heart. In two independent investigations, European scientists have found that Zofran may double the risk for cardiac septal defects, in which the walls of a baby’s heart fail to form properly.

As more and more researchers look into the possible effects of Zofran, some studies have produced conflicting results. A small Australian study, for example, found that Zofran may be able to increase the risk of major birth defects by 20% – but couldn’t consider that result “statistically significant.” In other words, the observed increase was so slight that it may just have been the product of chance. But if anything is certain, we need more scientists to investigate this issue. Several compelling studies have linked Zofran to an increased risk of major birth defects, but the drug’s true implications remain unclear.

What Do Real Doctors Think?

These results have caused a shift in obstetric practice. While the American College of Obstetricians and Gynecologists (ACOG) once put its weight behind the use of Zofran during early pregnancy, the organization has now pulled back from outright advocacy.

As US News & World Reports wrote in August of 2015, “further review of a commonly used morning sickness drug, ondansetron (Zofran), has prompted ACOG to pull back on supporting its use since more recent data suggest the drug may be linked to birth defects.” ACOG now suggests that pregnant women have open and fully-informative conversations with their obstetricians when discussing potential morning sickness remedies. That conversation, the group believes, should include details on the possible risks of taking Zofran.

When a pharmaceutical drug is indicated, the organization recommends that pregnant women try doxylamine and vitamin B6 as a first-line therapy. These are the active ingredients in Diclegis, a drug that was just approved specifically for nausea and vomiting in pregnancy. Zofran, on the other hand, has been “demoted” to a last-ditch treatment.

Zofran Side Effects In Pregnancy

Zofran’s potential side effects don’t just end with unborn children. In fact, the drug may pose significant dangers for mothers as well. Beyond diarrhea, headaches, fever and rashes, Zofran has been found to affect heart rhythms.

In 2012, the US Food & Drug Administration warned physicians that the drug could “affect the electrical activity of the heart” – potentially predisposing patients to a fatal condition known as Torsades de Pointes. Some researchers have gone even further, saying that Zofran’s effect on heart activity could be why babies exposed to the drug appear more likely to be born with cardiovascular defects.

Serotonin syndrome is another serious possibility. Serotonin is a neurotransmitter – a chemical that transmits messages between neurons in the brain. It’s also the key to Zofran’s effective alleviation of nausea and vomiting. Doctors believe that serotonin is crucial to triggering feelings of nausea. Zofran’s active ingredient ondansetron inhibits the ability of serotonin to initiate those feelings. But too much serotonin can be dangerous. In serotonin syndrome, the levels of serotonin get so high that patients begin to experience serious side effects, like:

  • shivering
  • diarrhea
  • muscle rigidity
  • fever
  • seizures

At its worst, serotonin syndrome can be fatal.

Parents Are Filing Zofran Lawsuits

Some women have taken Zofran during pregnancy, and found the drug effective in managing their morning sickness symptoms. But other mothers, often joined by their partners, have chosen to file birth defect lawsuits against GlaxoSmithKline – the company that manufactures Zofran. In fact, more than 280 families have already sued GlaxoSmithKline, accusing the company of hiding evidence that the drug can increase the risk for birth defects.

These parents aren’t alone in their legal battle. Back in 2012, the United States government sued GlaxoSmithKline, saying the multinational corporation had illegally marketed Zofran for off-label use during pregnancy. If true, these Justice Department allegations would certainly explain how Zofran became America’s leading morning sickness treatment so quickly. But GlaxoSmithKline continues to deny any wrongdoing, despite having settled the government’s case for a record-breaking $3 billion.

One thing remains true: Zofran’s product information makes no mention of a potential link to birth defects. Many parents say that’s completely unacceptable.