FDA orders safety review for some birth control pills

Bayer’s birth control pills will be reviewed by regulators after some studies suggested they may cause more blood clots than competing medicines.

Two recent reports in the British Medical Journal found a twofold to threefold greater risk of blood clots in women taking pills like Bayer’s Yaz, the Food and Drug Administration said Tuesday in a statement.

European regulators said last week that they were revising the products’ prescribing information to include the new safety findings.

While all birth control pills pose a risk of blood clots, the F.D.A. review focuses on the hormone drospirenone, found in Bayer’s Yaz, Yasmin, Beyaz and Safyral. The agency expects to have results later this summer of an 800,000-person study it commissioned to examine the risks.

In the meantime, regulators said doctors and patients should watch for symptoms of blood clots, including leg or chest pain.

The Yaz family of products generated $1.47 billion in sales last year for Bayer, or 3.3 percent of the company’s revenue.

“Patient safety is Bayer’s top priority,” the company said in an e-mail. “Bayer’s analysis of the overall body of available scientific evidence continues to support its current assessment about the safety of its oral contraceptives.”