Two recent studies in the U.S. and the U.K. show that women taking newer forms of oral contraceptives, which include Yaz, Yasmin and Ocella, are 2 to 3 times more likely to develop blood clots compared to those taking older birth control pills that rely on a different form of hormone. These results highlight what doctors have known ever since birth control pills were approved- that the mix of hormones needed to prevent pregnancy also promote clotting factors.
These newer birth control pills have warnings about increased risk of blood clots on the drugs’ labels.
Doctors insist that the absolute risk of developing blood clots is still small. Out of 100,000 women on the pill, only 31 would be expected to develop blood clots. Dr. Grace Lau, an ob/gyn at New York University Langone Medical Center, says, “If a woman has been on Yaz and has had no problems with it, then I don’t have a problem continuing to write her prescriptions for it… But for someone who hasn’t been on a contraceptive, as a provider I think about what would decrease their risk and I want the best for my patients. So this may not be the first thing I give them, since it may not be the best option they could possibly get.” She however stressed on the absolute risk for individual women that is still low, so each woman should decide for herself which option is right for her. Taking birth control, however, is not indicated for women who have a history of blood clots or are over 35 and smoke, since smoking increases the risk of clots.
Bayer, the maker of these drugs, is facing class action lawsuits in Canada and the U.S. related to Yasmin, Yaz and generic versions of the drug.