FDA Leaning Toward Adding Warnings on Blood Clot Risk From Newer Birth Control Pills

December 8, 2011 — Briefing documents released Tuesday indicate that FDA officials are leaning toward adding new information on risks to the labels of birth control pills containing the hormone drospirenone, the AP/Washington Post reports. FDA in a hearing on Thursday will ask an advisory panel to weigh in on concerns that the drugs could heighten the risk of blood clots more than other oral contraceptives (AP/Washington Post, 12/6). Drospirenone is a form of progestin found in Bayer's Yaz, Yasmin, Beyaz and Safyral birth control pills (Women's Health Policy Report, 9/27).

In the documents released Tuesday, FDA said there is conflicting evidence about the risk, but concluded that the information should still appear on labels "because of the consistency in recent reports for an increased risk" (AP/Washington Post, 12/6).

FDA's Reproductive Health Drugs Advisory Committee and its Drug Safety and Risk Management Advisory Committee will meet Thursday to discuss the available data and the final results of the FDA-commissioned epidemiologic study (Women's Health Policy Report, 9/27). FDA is not required to follow the committee's recommendations, though it often does (AP/Washington Post, 12/6).

Earlier this year, FDA launched a safety review after two studies published in the British Medical Journal found a two to three times greater risk of blood clots associated with birth control pills containing drospirenone compared with birth control pills containing levonorgestrel, another type of progestin.

After conducting its own review involving 800,000 women, FDA in a September statement said preliminary results suggest a 1.5 times greater risk of clots associated with drospirenone-containing contraceptives. However, six other studies show conflicting results, with some data showing a higher risk and others showing no increased risk. "As with all epidemiologic studies, there are methodological issues that make interpretation of these conflicting results complex," FDA said.

Bayer has said its analysis of available scientific evidence shows that the risk of developing a blood clot associated with pills containing drospirenone "is comparable" with that of other birth control pills (Women's Health Policy Report, 9/27).