Japanese pharmaceutical firm Shionogi & Co. is considering not recommending the use of its oral COVID-19 drug for pregnant women due to animal testing finding fetal abnormalities after it was administered, a source familiar with the matter said on Tuesday.

The Osaka-based drugmaker applied for approval of the drug with the Health, Labor and Welfare Ministry in February. But the finding may indicate a safety management system is needed to prevent pregnant women from taking the drug.

According to the source, the company found abnormalities in fetuses when pregnant rabbits were given the drug, which was higher in concentration compared with that taken by people during clinical trials.