Baby being diagnosed with congenital heart defect

Does Zofran Cause Heart Defects?

Baby being diagnosed with congenital heart defectIn our last article, we discussed a 2012 study conducted by researchers at Harvard and Boston Universities that linked the anti-nausea drug Zofran, a common “off label” morning sickness treatment,” to a more than two-fold increase in the risk of cleft palate. Public health experts found that women who were prescribed Zofran’s active ingredient during early pregnancy were 2.37 times more likely to deliver babies with that congenital defect.

But subsequent studies have repeatedly found an association between Zofran and another class of congenital abnormalities: congenital heart defects (CHD).

Researchers Find Association Between Zofran & Congenital Heart Defects

Three of the largest studies to investigate Zofran’s potential effects during pregnancy have found evidence of an increased risk for CHDs.

In 2013, a Danish study presented to the International Society of Pharmacoepidemiology reviewed every live birth in Denmark between 1997 and 2010. Ultimately, the researchers looked at more than 900,000 pregnancies, 1,368 of which had been exposed to Zofran’s active ingredient during the first trimester. Women who had been prescribed Zofran were found to be:

  • 60% more likely to deliver babies with heart defects
  • 2.1 times more likely to deliver babies with an atrial septal defect
  • 2.3 times more likely to deliver babies with a ventricular septal defect
  • 4.8 times more likely to deliver babies with an atrioventricular septal defect

At the same conference, a separate team of Danish researchers presented their own findings. This group used similar methods, but included only around 610,000 births between 2004 and 2011. While a higher proportion of women, 1,970, had been prescribed Zofran, half began taking the drug after 10 weeks of fetal development. Pregnancy experts have noted that birth defects are unlikely to develop after this point, even in fetuses exposed to a potentially harmful substance. Prominent researchers have said that this fact may have “diluted” the risks demonstrated by the second Danish study.

Even so, the paper’s supplemental materials indicated that women exposed to Zofran were at an increased risk of delivering babies with cardiac septal defects. These women were:

  • 22% more likely to deliver babies with cardiac septal defects
  • 41% more likely to deliver babies with a ventricular septal defect
  • 400% more likely to deliver babies with an atrioventricular septal defect

One year later, a Swedish group published a similar study in the journal Reproductive Toxicology. Reviewing every pregnancy in Sweden between 1998 and 2012, the team concluded that women who were prescribed Zofran during the first trimester were:

  • 62% more likely to deliver babies with a CHD
  • 205% more likely to deliver babies with a cardiac septal defects

Obviously, current findings suggest an association between Zofran exposure and congenital heart defects. But more specifically, scientists have linked Zofran to an increased risk for a specific category of CHDs: cardiac septal defects.

What Are Cardiac Septal Defects?

Heart without congenital birth defects

To the right, we can see a diagram of the human heart. Marked “RA” and “LA” are the organ’s uppermost chambers: the right and left atrium. Below those, marked “RV” and “LV,” are its lower chambers: the right and left ventricle.

Marked as “TV” and “MV” are the tricuspid and mitral valves. While the diagram makes these structures look like large openings, they are actually tight valves that can open and close as the heart beats.

In healthy human hearts, each of the heart’s four chambers is separated from the others by several strong walls. We can see one of these walls in the diagram, a thick barrier separating the right ventricle (RV) from the left ventricle (LV). These walls are called “septum,” and they ensure that blood pressures remain stable and that blood flows where it should.

Children with cardiac septal defects are born with one or more holes in these walls, and that’s why these conditions are commonly referred to as “hole in the heart” defects. As a result, blood doesn’t flow properly through their hearts.

An atrial septal defect is a hole that allows blood to flow from one atrium to another, rather than down to the ventricles. Likewise, ventricular septal defects involve a hole between the ventricles. While atrioventricular septal defects can vary in their precise nature, most involve a hole near the heart’s center, where the atria on top meet the ventricles below.

Congenital heart defect linked to Zofran

Left to right: Atrial Septal Defect, Ventricular Septal Defect, Atrioventricular Septal Defect

To find a detailed overview of cardiac septal defects, including potential complications and treatment options, visit this page at the Heart Birth Defect Resource Center.

Have Families Named Congenital Heart Defects In Zofran Birth Defect Lawsuits?


Out of at least seven complaints that have been filed in the ongoing Zofran litigation, five have been brought by the parents of children who were born with CHDs.

Filed in the US District Court of the Eastern District of Pennsylvania, the first Zofran birth defect lawsuit claims that plaintiff’s two daughters were both born with congenital heart defects after being exposed to Zofran in the womb. While the complaint, registered under case number 2:15-cv-00709-PD, does not specify diagnoses, court documents note that one of plaintiff’s daughters “was forced to undergo surgery to repair the hole in her heart” in 2011. Cardiac septal defects are often referred to as “hole in the heart” defects.

In case number 1:15-cv-10429, filed in the US District Court of the District of Massachusetts, a mother claims that prenatal exposure to Zofran caused her daughter to develop three heart defects, including one cardiac septal defect. She names atrial septal defect, right ventricular hypertension and aortic arch hypoplasia in her complaint.

In the third Zofran birth defect lawsuit, filed under case number CGC-15-544524, parents in San Francisco allege that Zofran prescribed as an “off label” morning sickness treatment caused their unborn child to develop bicuspid aortic stenosis. This CHD occurs when a heart valve, normally formed from three flaps or “leaflets,” has only two leaflets. Unable to open properly, the abnormal valve can leak blood into heart chambers. Over time, bicuspid aortic valves collect calcium deposits, becoming stiff and narrowed. This condition, known as “stenosis,” can impede blood flow to the brain and result in potentially life-threatening complications.

Filed in the Superior Court for the State of California, County of Alameda, under case number RG15761042, plaintiff in the fourth Zofran claim says that exposure to Zofran during early pregnancy caused her son to develop supraventricular tachycardia (SVT), an abnormally fast heart beat. SVT is the result of abnormalities in the heart’s electrical system.

In case number 5:15-34, a mother from Texas says that after she was prescribed Zofran to treat morning sickness, her newborn son was diagnosed with a heart murmur and thickened arteries. Heart murmur, a characteristic “whooshing” sound, is a common symptom of cardiac septal defects, and improper blood flow can cause arteries to become abnormally thick.

What About Other Families?

If you were prescribed Zofran as an “off label” morning sickness treatment during the first trimester, and then delivered a baby with congenital heart defects, you may be eligible to file a claim against Zofran’s manufacturer. is sponsored by Monheit Law, a personal injury firm led by Michael Monheit, Esq. Monheit Law has gathered together an alliance of recognized plaintiffs’ attorneys to investigate the claims of parents who believe that prenatal exposure to Zofran may have contributed to a child’s major birth defects. Our attorneys are dedicated to protecting the rights of families and birth defect survivors nationwide. We are currently providing free consultations to any family interested in learning about their own case eligibility. To speak with an experienced lawyer today, call 1-877-620-8411 or fill out our contact form.