Two mothers from Louisiana are suing GlaxoSmithKline (GSK), alleging that company’s drug Zofran caused their daughters to be born with severe heart defects.

The mothers, Stacy C. and Ashley S., are suing on behalf of themselves and of their respective minor children. Both mothers took Zofran during pregnancy and then gave birth to children afflicted with life-threatening birth defects.

Stacy’s daughter was born in 2010 with a perimembranous ventricular septal defect, atrial septal defect and intermittent tachypnea. Ashley’s daughter was born in 2005 with accelerated ventricular arrhythmia, which Ashley says was nearly fatal shortly after birth. The child required continuous medical monitoring and testing for her first five years of life.

Both mothers now attribute their daughters’ birth defects to the Zofran they took early in their pregnancies. They say neither they nor their physicians knew about the risk of birth defects associated with Zofran. They claim they would not have taken Zofran had they been informed about those risks.

Zofran Birth Defects

Zofran, also known by its generic name ondansetron, is approved by the FDA as a treatment for nausea and vomiting associated with chemotherapy, radiotherapy, and recovery from surgery.

To date, the FDA has not approved Zofran as a treatment for morning sickness. While no studies have been conducted on the effects of Zofran in pregnant women, Stacy, and Ashley say that the 1980s studies conducted on animals revealed evidence of “toxicity, intrauterine deaths, and malformations in offspring.”

Through the 1990s and 2000s, GlaxoSmithKline received dozens of reports of birth defects allegedly linked to Zofran use, but did not disclose that information to patients or physicians, according to the plaintiffs.

For use in pregnant women, the FDA currently places Zofran in pregnancy Category B, meaning the drug should be used during pregnancy only if clearly needed. Stacy and Ashley say GlaxoSmithKline was under a legal duty to put Zofran in either Category D, meaning use during pregnancy is not recommended unless the mother’s life is in danger or if it is necessary to treat a serious disease for which no other remedy can be used, or in category X, meaning the risks to the fetus clearly outweigh any possible benefit.

In 2012, GlaxoSmithKline was called on the carpet for allegedly promoting Zofran as a morning sickness medication. That year, 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.

The Zofran Birth Defects Lawsuit is Case No. 15-1815, in the U.S. District Court for the Western District of Louisiana.