(BOSTON) -- New forms of birth control may present greater risk of blood clots than earlier types, researchers say.
Two new studies add to the emerging evidence that oral contraceptive pills with a new type of progestin hormone, drospirenone (e.g. Yasmine, Yaz, Ocella), have a greater risk of blood clots than pills containing an older progestogen hormone, levonorgestrel (e.g. Levlite, Levlen).
Both studies, published online in the British Medical Journal, found a two-to-three-fold increased risk of clots in women who take drospirenone-containing pills as compared to levonorgestrel-containing pills.
Bayer Pharmaceuticals, the makers of Yazmine, Yaz and Ocella, have come under fire in recent years for the safety of the pills. The company is also facing several lawsuits because of the incidence of blood clots associated with the pills.
The authors of the studies feel that now is the time for a systematic review on this topic.
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