(WASHINGTON) -- Yaz was pitched as the blockbuster birth control pill with benefits, the choice for women desperate for relief from severe PMS and acne. But now, several new independent studies have found that Yaz carries higher blood clotting risks than other leading birth control pills, leading to new scrutiny from safety regulators.
Former Food and Drug Administration Commissioner Dr. David A. Kessler, who is now working for lawyers suing Bayer, which makes Yaz, is accusing the drugmaker of concealing the contraceptive's health risks.
"Bayer violated its duties under FDA regulations and state law by selectively presenting data as to [blood clotting] events," Kessler said in court documents, citing studies that Bayer itself conducted but allegedly misreported to regulators.
He indicated that if he had been head of the FDA in 2000 and knew what he knows now, he may not have approved the drug.
"In my opinion, had I, or a medical review officer, known these facts prior to approval, further investigation would be warranted," he wrote.
Citing conflicting safety studies, the FDA is holding hearings on Thursday to determine whether new safety measures, like package label changes, are warranted.
Bayer maintains that Yaz is safe.
"Based on a thorough assessment of the available scientific data, Bayer believes that its drospirenone-containing products are safe and effective and have a favorable benefit-risk profile when used in accordance with U.S. product labeling," Bayer spokeswoman Rose Talarico told ABC News.
Copyright 2011 ABC News Radio