Babies at greater risk for heart defects if mothers took Zofran during pregnancy

March 25, 2016 – San Diego, CA  Morning sickness. Most pregnant women will experience it — up to 85 percent in fact. Usually it’s a relatively manageable, albeit uncomfortable, symptom of pregnancy, but the severity of it varies from woman to woman. When morning sickness becomes too much to bear, some women may turn to their doctors for help.

Between 1982 and 2013, there was no drug on the market approved by the U.S. Food and Drug Administration (FDA) to treat morning sickness in pregnant women. But that didn’t stop doctors from prescribing certain anti-nausea drugs off-label. By the end of 2014, 97.7 percent of prescriptions written in the U.S. for the treatment of morning sickness were for medications not approved for use in pregnant women, according to a study published in December of that zofran heart defects

Ondanestron, known by the name-brand Zofran, became a popular choice for doctors. Prescriptions for ondanestron rose from 50,000 monthly prescriptions in 2008 to 110,000 by the end of 2013, according to the same study.

Zofran was originally manufactured by British pharmaceutical giant GlaxoSmithKline, but was taken over by Switzerland-based Novartis Pharmaceuticals last year. It was approved by the FDA in December 1992 to prevent nausea and vomiting caused by cancer, chemotherapy, radiation therapy and surgery. Zofran and its generics belong to a class of drugs called 5-HT3 receptor antagonists, which work by blocking the action of serotonin in the body to prevent nausea and vomiting.

Zofran and other ondanestron drugs have never been approved by the FDA to prevent nausea and vomiting in pregnant women. There have also been no significant studies conducted to determine whether Zofran is safe to use during pregnancy.

Despite this fact, doctors have been prescribing Zofran and its generics to thousands of pregnant women for years, and now women are speaking out against the drug alleging it caused serious harm to their babies.

Heart defects linked to Zofran

Only a few studies have been published in peer-reviewed literature examining the safety of ondanestron-use in pregnant women. Of those few studies, only one followed actual pregnant women; the others analyzed data from birth and prescription drug registries.

One of the studies that analyzed data from registries, presented in 2013 at the International Society of Pharmacoepidemiology Conference, indicated a two-fold increased risk of heart defects in the babies of women taking ondanestron during pregnancy. This translates into a 30 percent increased risk when taking Zofran or its generics.

Another study published in Reproductive Toxicology in 2014 found that the risk for cardiovascular defects increased nearly two-fold when mothers took ondanestron during pregnancy. Babies were especially susceptible to cardiac septum defects, the study found.

What are cardiac septum defects?

Cardiac septum defects include Atrial Septal Defect (ASD) and Ventricular Septal Defect (VSD).

ASD occurs when a hole exists in the wall separating the top two chambers of the heart. VSD occurs when a hole exists in the wall separating the two lower chambers of the heart. Both defects can be life-threatening if not treated and may require surgery to fix.

Atrial Septal Defect

All babies are born with an opening between the upper chambers of the heart, but that hole normally closes or becomes very small within several weeks or months after the baby is born, according to the American Heart Association.

When a baby is born with ASD and the hole is very large, extra blood is pumped into the lung arteries which could make the heart and lungs work harder than normal. This added stress could damage the lung arteries over time.

There will usually be a murmur or other abnormal heart sound present in children and babies with a large ASD. Doctors are able to detect the sound using a stethoscope.

If a baby is born with a large ASD, open-heart surgery may be necessary. Doctors may also use cardiac catheterization to plug up the hole. A large ASD can cause permanent damage to the lungs if not treated.

Ventricular Septal Defect

Babies born with VSD can have either small or large holes in the heart. Infants who are born with large holes may have difficulty feeding and growing at a normal rate and symptoms may not occur until several weeks after birth, the American Heart Association says.

A large hole allows more blood to flow into the lung’s blood vessels, which could cause permanent damage over time. Open-heart surgery may be necessary to repair the VSD. If a baby is very ill, has more than one VSD or if the VSD is in an unusual location, he may require a temporary operation in which doctors place a band around the pulmonary artery to stop excess blood flow into the lungs. When the baby is older, he will require a second surgery to remove the band and repair the VSD.

Other possible birth defects associated with Zofran

A 2011 study funded by the Centers for Disease Control and Prevention found that the risk of babies being born with cleft palate were increased more than two-fold for women taking ondanestron during the first trimester of pregnancy.

A cleft palate is a split or opening in the roof of the mouth and occurs when the tissues that make up the roof of the mouth do not join completely together. The roof of the mouth is formed between the sixth and ninth weeks of pregnancy.

Apart from the obvious physical difference between a baby born with a cleft palate and a baby born without, cleft palates can cause eating problems, ear infections, hearing loss, speech and dental problems.

Eating problems: The cleft palate may make it more difficult for babies to feed. They may not be able to breastfeed and may require a specifically designed baby bottle to feed.

Ear infection/hearing loss: Infants with cleft palate have an increased risk of chronic ear infections due to buildup in the middle ear. If ear infections go untreated, they could lead to hearing loss.

Speech problems: If the cleft palate is not surgically treated, children may develop speech problems, including a nasal sound when speaking or speech that is difficult to understand.

Dental problems: Tooth development may be affected if the cleft extends through the upper gum.

To treat a cleft palate, the parents of the infant or child will need to seek the help of a plastic surgeon, and possibly an ear, nose and throat doctor, oral surgeon and orthodontist.

Lawsuits forming for all types of Zofran birth-related complications

Women are filing lawsuits against GlaxoSmithKline claiming the company failed to warn doctors and consumers about the possible risks associated with the use of Zofran during pregnancy. If you took Zofran during your pregnancy and your baby was born with a heart defect, club foot, cleft lip or cleft palate, call the Hood National Law Group today. You may be entitled to a large cash award. Call 1-800-214-1010 today to see if you qualify, or use the form on the right-hand side of your screen.


American Journal of Obstetrics and Gynecology; Gideon Koren; “Treating morning sickness in the United States – Changes in prescribing are needed,” December 2014

Therapeutic Drug Monitoring; Gideon Koren; “Scary Science: ondansetron safety in pregnancy – two opposing results from the same Danish registry,” Jan. 9, 2014

International Society of Pharmacoepidemiology Conference; Andersen JT, Jimenez-Solem E, Andersen NL, Poulsen HE; “Ondanestron Use in Early Pregnancy and the Risk of Congenital Malformations – A Register Based Nationwide Control Study,” 2013

Reproductive Toxicology; Danielsson B, Wikner BN, Källén B; “Use of ondansetron during pregnancy and congenital malformations in the infant,” December 2014

National Birth Defects Prevention Study; Anderka M, Mitchell AA, Louik C, Werler MM, Hernández-Diaz S, Rasmussen SA; “Medications used to treat nausea and vomiting of pregnancy and the risk of selected birth defects,” Nov. 19, 2011

American Heart Association:

American Heart Association:

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