According to The Globe and Mail, the study was led by Frits Rosendaal of the department of clinical epidemiology at Leiden University Medical Centre in the Netherlands. Over 1,500 women who suffered blood clots in their legs or their lungs while taking oral contraceptives were compared with more than 1,700 women of similar backgrounds who did not suffer blood clots.
The researchers found that oral contraceptives with the lowest amount of estrogen carried the lowest risk of blood clots. However, the type of progestin a pill contained also made a difference. For instance, pills made with drospirenone, such as Yasmin and Yaz, showed a 6.3-fold increase in risk of blood clots. The highest risk was seen among users of oral contraceptives that used desogestrol, which had 7.3 times the risk of blood clots. Contraceptive pills containing levonorgestrel, however, increased the risk of clots by only 3.6-fold, The Globe and Mail said. All of the pills studied were effective in preventing pregnancy.
“The safest option with regard to the risk of venous thrombosis is an oral contraceptive containing levonorgestrel combined with a low dose of estrogen,” Dr. Rosendaal told the Globe an Mail.
As we’ve reported previously, lawsuits have been filed around the U.S. by women who say they suffered serious side effects from contraceptive pills made with drospirenone, including Yaz and Yasmin. The women involved in these lawsuits claim they experienced serious blood clots, including deep vein thrombosis and pulmonary embolism, as well as strokes. These pills have also allegedly been associated with heart attacks and deaths in young women.
In October 2008, the U.S. Food & Drug Administration (FDA) cited two Yaz commercials for deceptive claims. In a warning letter, the FDA faulted Bayer, the drug’ smaker, for overstating the benefits of Yaz. The FDA also criticized the ads for containing fast-moving images and background music that might be distracting to viewers. These elements were aired while information about potential Yaz side effects â€“ including blood clots â€“ was described. The FDA warning letter said the television commercials minimized the risks posed by Yaz.
Bayer ended up pulling the misleading ads. It also reached an agreement with the FDA and 27 state attorneys general to run new TV spots correcting the misinformation from the pulled commercials. They began running in early 2009.