WASHINGTON — Safety concerns with the popular birth control pill Yaz increased Thursday as federal health scientists reported the Bayer drug and other newer birth-control treatments appear to increase the risk of dangerous blood clots more than older medications.
A new study released by the Food and Drug Administration reviewed the medical history of more than 800,000 U.S. women taking different forms of birth control between 2001 and 2007. On average, women taking Yaz had a 75 percent greater chance of experiencing a blood clot than women taking older birth-control drugs.
Yaz contains estrogen along with a next-generation synthetic hormone called drospirenone, which is known to increase potassium levels in the blood. FDA compared medical records of women taking the drug with those taking the older drug levonorgestrel.
The agency also reported higher complications in women using the Ortho Evra patch from Johnson & Johnson and the Nuvaring vaginal ring from Merck & Co. Inc.
The FDA said it hasn’t reached a final conclusion on the drugs’ safety but will hold a meeting with scientific advisers Dec. 8.
