Medical Researchers Find Increased Risk Of Heart Defects And Cleft Palates In Babies Born To Women Using Zofran
Women with severe morning sickness who were prescribed Zofran (ondansetron) -- a GlaxoSmithKline drug approved by FDA for the prevention of nausea and vomiting associated with chemotherapy and radiotherapy -- have had babies born with heart-related birth defects and other congenital malformations such as cleft palate and/or cleft lip.
For some background facts regarding this emerging drug-safety issue we begin with a June 2014 investigative news report, "Birth defects blamed on unapproved morning sickness treatment", which was published by the Toronto Star newspaper. Here are three important points taken from that article:
[#1] Because most women experience nausea and vomiting during the first trimester, they would be taking the drug at the same time the fetus is most vulnerable to developing malformations and deformities.
Roughly 10 to 15 per cent of pregnant women receive drugs to treat morning sickness, according to a recent U.S. study.
[#2] In 2012, the U.S. Department of Justice reached a $3-billion settlement with GlaxoSmithKline after the government alleged the company promoted the off-label uses of several drugs, including Zofran, the company’s brand-name version of ondansetron.
Court documents alleged the company gave doctors kickbacks to prescribe the drug for morning sickness and disseminated false information about Zofran’s safety and effectiveness.
[#3] The Star contacted [GlaxoSmithKline about] the side-effect reports.
Glaxo said “the safety of [Zofran (ondansetron)] for use in human pregnancy has not been established. . . . (The company) monitors and reports all adverse event reports . . . and works closely with regulatory authorities in Canada to include relevant safety information for physicians and patients within our product labels.”
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The most concerning medical study to date about the association of Zofran with birth defects is by a group of Danish doctors, "Ondansetron use in early pregnancy and the risk of congenital malformations – a register based nationwide cohort study", which was first presented in 2013.
From a document describing that Zofran - birth defects medical research:
... Only limited data concerning the safety of [Zofran (ondansetron)] in pregnancy is available.
Therefore we conducted a nationwide cohort study testing the hypothesis use of [Zofran (ondansetron)] during the first trimester was associated with a higher prevalence of congenital malformations.
The study included all women giving birth in Denmark 1997 and 2010.... The primary outcome was the prevalence of major congenital malformations according to the EUROCAT classification system and subgrouping among first trimester users of [Zofran (ondansetron)] compared to non-users. Exposure was defined redemption of one prescription of [Zofran (ondansetron)] in the first trimester of pregnancy.
We identified 897 018 births in the study period. 1248 women redeemed a prescription of [Zofran (ondansetron)] in the first trimester of which 58 (4.7%) had offspring with a congenital malformation compared to 31357 (3.5 %) in the unexposed group. The odds ratio (OR) of having an offspring with a major malformation after exposure to [Zofran (ondansetron)] was 1.3 (CI95% 1.0-1.7). This was mainly caused by an increased prevalence of heart defects (OR=2.0 (CI95% 1.3-3.1)....
We found a doubling in the prevalence of major congenital heart defects in children whose mothers redeemed a prescription of [Zofran (ondansetron)] in the first trimester of pregnancy.
An earlier medical journal article from 2011, "Medications Used to Treat Nausea and Vomiting of Pregnancy and the Risk of Selected Birth Defects", indicated that Zofran use as a morning-sickness drug during pregnancy results in an increased risk of cleft palate (CP).
An update on the 2013 Danish medical research presentation about Zofran use during pregnancy was provided in the June 2014 Toronto Star news report:
Those researchers... have since expanded the study to include more births and arrived at the same conclusion; they recently submitted their results to an academic journal, the lead researcher told the Star.
We will continue to monitor this relatively new drug-safety issue of Zofran use by pregnant women being linked to birth defects such as congenital heart defects and cleft palate, as well as possibly other congenital malformations in children born to those women.