Birth Defect Risk Unknown for Most New Drugs
Mon Sep 2, 2002  By Alison McCook 

NEW YORK (Reuters Health) - More than nine-tenths of drugs approved since 1980 have not been properly tested to ensure they do not cause birth defects if taken by pregnant women, study findings show. 

According to researchers based at the University of British Columbia in Vancouver, Canada, new drugs must be tested to determine if they cause birth defects in pregnant animals before they are approved by the US Food and Drug Administration. 

However, what a drug does in animals is not always what it does in humans, they note--so once a drug is approved, researchers need to track what happens in human patients, and use that information to determine whether pregnant women who take the drug are putting their fetuses at risk. 

However, as W.Y. Lo and Dr. J.M. Friedman show, these follow-up studies have not been performed for the vast majority of new drugs. As such, more than 90% of new drugs are still considered to have an "undetermined" risk of producing birth defects, according to the report in the September issue of the journal Obstetrics & Gynecology.

Many women need to take drugs for a variety of reasons during pregnancy, and not knowing the risks of these drugs can be frustrating, Friedman told Reuters Health.

"My experience is that many members of the general public, both pregnant women and their partners, are surprised and frustrated about how little we really know about the safety of medications in pregnancy," Friedman said. 

In an interview, Friedman said that the companies that manufacture the drugs often have no financial incentive to conduct further studies on birth defects once the drug is FDA-approved. Proper studies cost money, the researcher noted, and there is usually no regulatory requirement that the companies perform these tests. 

SOURCE: Obstetrics & Gynecology 2002;100:465-473. 
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