A hormone in some birth control pills made by Bayer may cause dangerous blood clots, studies have found. The pills have been linked to several recent deaths, but a ban is considered unlikely.

Birth control pills containing certain hormones like drospirenone are twice as likely to cause blood clots - or thrombosis - than older pills, according to two recent studies published in the British Medical Journal. In Switzerland, a 21-year-old girl died in September after taking a drospirenone-containing contraceptive from Bayer's Yasmin line. In Germany, 25-year old Felicitas Rohrer collapsed in July with three thromboses in her lung. Since 2001, seven women in Germany have died while taking a contraceptive from the Yasmin family.

In total, 130 cases of adverse drug reaction have been reported to Germany's Federal Institute for Drugs and Medical Devices. However, not all of them are related to thrombosis, Ulrich Hagemann, head of the institute's department of drug safety, told Deutsche Welle.

Bayer denies higher risk factor
Birth control pills that contain the hormone drospirenone are particularly attractive to women since they promise less weight gain and clearer skin. But they also thicken the blood, thereby increasing the risk for thrombosis. The Yasmin line offers five different contraceptives with the hormone: Yasmin, Yaz, Yasminelle, Aida and Petibelle.

Bayer said that it is known that the risk for venous thromboembolism, or blood clots in the veins, can be increased when starting the pill. Earlier studies funded by Bayer concluded that the drospirenone-containing pills held no higher risk than older, so-called second-generation pills. But "arznei telegram," an independent publication for doctors and pharmacists, said the studies were not valid due to "massive method-related deficiencies."

Lawsuits in the US

Bayer, who earns 1.2 billion euros ($1.8 billion) from the worldwide sales of the Yasmin line, confirmed to Deutsche Welle that it currently faces 129 lawsuits in the United States, brought by women who say they've developed health problems after taking Yaz or Yasmin.  "Bayer is still in the process of gathering information on these cases, and the complaints we have received so far pertained to side effects that are warned about in our approved labeling and the labeling for other oral contraceptives," said spokesperson Friederike Lorenzen. "Bayer will defend itself vigorously against these lawsuits."

Critics like the Coalition against Bayer Dangers claim advertising focused too much on lifestyle factors like weight loss and skin appearance. A contraceptive should first and foremost work as a safe contraceptive, said Philipp Mimkes of the Coalition against Bayer Dangers. "I got the first package in a nice little silver box with a mirror and make-up brush inside; it seemed very nice, so why shouldn't I take it? But I never heard that this pill has a much higher risk of pulmonary embolism than other pills," said Felicitas Rohrer.

Ban unlikely
Ulrich Hagemann from the Federal Institute for Drugs and Medical Devices said 20 out of 100,000 women who take an oral contraceptive from the second-generation, which were developed in the 1970s, develop thromoembolic symptoms. For the newer, third-generation pills - and also for contraceptives containing the hormone drospirenone, like Yasmin - women face a risk twice as high, with 35 to 40 women out of 100,000 experiencing thromboembolic effects each year.  

"For the same dose of estrogen and the same length of use, oral contraceptives with desogestrel, gestodene, or drospirenone were associated with a significantly higher risk of venous thrombosis than oral contraceptives with levonorgestrel," concluded the Danish study in the British Medical Journal.  

Felicitas Rohrer wants the Yasmin family banned from the market. But, according to Ulrich Hagemann from the Federal Institute for Drugs and Medical Devices, a ban is unlikely. "I think there is no good scientific reason as the third (generation of) oral contraceptives has been on the market for more than ten years and we now have a new type of oral contraceptive with the same risk," said Hagemann, referring to the Yasmin label. "You couldn't argue for taking these off the market and keeping the others on the market."

Risk not mentioned
The Coalition against Bayer Dangers therefore demands a complete ban of all third generation contraceptives with a higher thrombosis risk compared to the second generation. The Federal Institute for Drugs and Medical Devices is looking into changing the product information to reflect the new data coming from the recent studies. "There is a need from my point of view to change the text" in the product information that accompanies the pills, said Hagemann.

According to the recent studies published in the British Medical Journal, second-generation contraceptives with the hormone levonorgestrel that have been used since the 1970s are currently considered the safest option for women who want to use birth control pills.  

(By Sarah Steffen, Deutsche Welle, 21/10/2009)