The Bayer birth control pills Yaz and Yasmin may increase the risk of blood clots by as much as 75% when compared to older birth control pills, according to a study conducted by the FDA. 

The FDA released a new drug safety report (pdf) on Yaz, Yasmin and all drugs made with the progestin drospirenone last week, announcing that its own study has found significant increased risk of blood clots with the contraceptive pills.

The findings come just weeks before an FDA advisory committee meeting to discuss the safety of Yaz, Yasmin and related birth control pills. It was also released the same week that a study published in the British Medical Journal found that the risk of blood clots doubled with Yaz, Yasmin and other newer birth control pills.

The FDA study looked at 800,000 women between 2001 and 2007 and involved the agency, Kaiser Permanente, Vanderbilt University and the University of Washington. Researchers found that, overall, drospirenone-based birth control pills increased the risk of blood clots, known as venous thromboembolic events (VTE), by 75% over pills using the progestin levonorgestrel. It also doubled the risk of arterial thrombotic events (ATE), like heart attacks and strokes in users who were new to birth control, and many of the health problems appear to come less than three months after beginning a Yaz or Yasmin birth control regimen.

Drospirenone is a newer type of progestin that is used in combination oral contraceptives that also include estrogen. It was originally introduced by Berlex Laboratories in Yasmin. Once Berlex was acquired by Bayer Healthcare an updated version of Yasmin was introduced called Yaz. More recently, Bayer introduced a third version, marketed as Beyaz, which includes a folate supplement. Generic versions of Yaz and Yasmin are also now available from other manufacturers. Generic versions of Yaz and Yasmin include Ocella, Gianvi, Loryna, Safyral, Syeda and Zarah.

The findings appear to back up claims raised in hundreds of Yaz lawsuits and Yasmin lawsuits filed on behalf of women who experienced serious and sometimes fatal blood clots after using the birth control pills. The complaints allege that Bayer failed to adequately warn about the risk of blood clots from side effects of Yaz and Yasmin, placing their desire for profits before patient safety by minimizing the risk in aggressive direct-to-consumer advertisements for the birth control pills.

The new data will be presented on December 8 at a joint meeting of the Reproductive Health Drugs Advisory Committee and the Drug Safety and Risk Management Advisory Committee. Both are panels of drug experts who will analyze the existing data on Yaz and Yasmin and make recommendations to the FDA on what course it should follow to protect women’s health. The committees’ findings are not binding, but they usually factor in heavily in the FDA’s final decision.

In addition to problems with drospirenone based pills, the study also found significantly increased risk of blood clots linked to the Ortho-Evra patch and the NuvaRing contraceptive device. Both appeared to raise the risk of VTE by about 55% over levonorgestrel, but their side effects took more than a year, on average, to begin to affect users, unlike Yaz and Yasmin.

Tags: Bayer, Beyaz, Birth Control Patch, Birth Control Pill, Birth Control Ring, Blood Clot, Deep Vein Thrombosis, Gianvi, Heart Attack, Loryna, NuvaRing, Ocella, Ortho Evra, Pulmonary Embolism, Safyral, Stroke, Syeda, Yasmin, Yaz, Zarah