GlaxoSmithKline lost its bid to end multiple lawsuits against the company alleging that its anti-nausea drug Zofran (ondansetron) caused birth defects.

Multiple parents sued the drugmaker in the U.S. District Court for Massachusetts alleging that their children were born with birth defects due to prenatal exposure to the drug.

The plaintiffs argued that pre-clinical studies in the 1980s revealed that Zofran ingested by mammals during pregnancy crosses the placental barrier, exposing the fetus to the drug. Subsequent studies confirmed the same effects in humans.

GSK moved to end 72 individual cases in June arguing that the plaintiffs did not provide evidence to link their children’s birth defects with the drug and asked the judge to rule against them. Fourteen cases were voluntarily dismissed by the plaintiffs, leaving 58 cases to be decided.

In a ruling on the multidistrict litigation, U.S. District Court Judge Dennis Saylor ruled in favor of GSK for five cases, but kept the other 53 cases alive. Forty-eight of those cases allege that Zofran caused defects of the palate or lip.