Blood clots are a well-known risk of taking birth control pills. Now the FDA is investigating oral contraceptives that contain drospirenone, such as Yaz and Yasmin, after new research suggests that these pills increase the risk of blood clots above that of other oral contraceptives.

Most birth control pills combine estrogen with another female sex hormone, progestin. In two studies published in the British Medical Journal in April, pills containing drospirenone, a type of progestin, were found to carry a two- to three-fold higher risk of venous thromboembolism, or a blood clot in a deep vein, than pills containing a different progestin, levonorgestrel.

The agency said in a safety alert posted online Tuesday:

“Other studies have not reported an increase in risk. The FDA is currently evaluating the conflicting results from these studies and will look at all currently available information to fully assess the risks and benefits of drospirenone-containing birth control pills.”


Such pills include Yaz (generics Gianvi and Loryna), Yasmin (generics Ocella, Syeda, and Zarah), Beyaz, and Safyral, according to the FDA.

The absolute risk of a blood clot, no matter which pill, is still low, according to the British Medical Journal research. So women shouldn’t stop taking the pills, advises the FDA, unless they’ve checked with a healthcare professional or start having leg or chest pain or shortness of breath, symptoms of a blood clot.

But the new studies—and now the FDA’s scrutiny—are likely to fan the controversy over the safety of Yaz, one of the most popular birth control pills.

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healthkey@tribune.com

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