When Marquita Smiley started experiencing severe morning sickness, she was prescribed the anti-nausea medication Zofran. Although Zofran was never approved or studied for use in pregnant women, if quickly became a popular off-label treatment for morning sickness. Smiley took the drug several times a week, and in her fifth month, she had an ultrasound that forever changed her life.

The ultrasound revealed that her baby’s heart was severely underdeveloped. Just days after her baby son was born, he had to undergo open heart surgery. As if this wasn’t torture enough for Smiley, at two months old, her son had a heart transplant.

Smiley maintains that if she had been properly warned of the birth defect risks associated with Zofran, she would never have taken the drug while pregnant. In her lawsuit, she claims Zofran’s manufacturer, GlaxoSmithKline (GSK), illegally promoted Zofran for off-label use to treat morning sickness in pregnant women.

But Smiley is not alone. More than 300 other families filed lawsuits against GSK alleging they were not adequately warned that exposing babies to Zofran in utero could cause debilitating birth defects. The lawyers handling the Zofran litigation are currently trying to agree on how to proceed with the discovery process.

Although GSK continues to deny any wrongdoing, plaintiffs point to a massive 2012 settlement with the U.S. Department of Justice. GSK paid a whopping $3 billion to resolve allegations of fraud and failure to report safety data that included the illegal promotion of Zofran.

Zofran was initially approved to treat nausea and vomiting in chemotherapy patients and patients who have undergone surgery. Pregnant women were specifically excluded from the clinical trials that led to Zofran’s FDA approval.

Plaintiffs in the Zofran litigation believe GSK wanted to capitalize on the potential to market the drug to treat morning sickness without conducting necessary clinical trials. But GSK’s actions will cost them. Families in the litigation are unwavering in their desire to hold GSK responsible, and it is unlikely the company will come out of this unscathed.