No. The Makers of Zofran failed to test its drug in humans to make sure it would be safe for treating morning sickness in expectant mothers.
Zofran (ondansetron) is only approved by the FDA to treat nausea and vomiting in chemotherapy and surgery patients. This drug is not approved for use in pregnant women. Neverthless, Zofran (ondansetron) has gained an increasingly widespread market share as an “off label” prescription for expectant mothers.
There is no law or regulation stopping doctors from prescribing drugs off-label. There are some innovative off-label uses of drugs that have been safe and effective treatment for certain conditions. But many off-label prescriptions are written with no solid scientific proof that the drug will be safe or effective. This is exactly what appears to have happened with the off-label use of Zofran in pregnant women: There is increasing evidence that Zofran can cause cleft lip, cleft palate, and heart defects in the children of mothers who took this drug for morning sickness early in their pregnancy.
Because most women experience nausea and vomiting during the first trimester, they would be taking the drug at the same time their fetus is most vulnerable to developing malformations and deformities.