A group of Canadian women is suing the makers of popular birth control pills Yaz and Yasmin.
The women claim they were not adequately warned about a higher than usual risk for stroke and other health problems before using the drugs.

Yaz and Yasmin, made by Bayer's Inc., are oral contraceptives that are used by thousands of women across the country, but have some users reporting racing hearts, strokes, and in some cases, gallbladder problems that lead to surgery.

Siskinds LLP filed the lawsuit against Bayer's on Wednesday, although it has yet to be court-certified.

The pills were approved by Health Canada in 2004 and 2008. More than two million prescriptions for the contraceptives were filled in 2009 according to IMS Health Canada.

Bayer has said its oral contraceptives have been studied all over the world and are "safe and effective" when used according to the product labelling.

 One of the women named as a plaintiff in the suit is Ann Schwoob, a 33-year-old from Vineland who was prescribed Yasmin by her family physician last June. 

In August, she went to hospital in Grimsby with chest pains, which the statement of claim says were diagnosed as pneumonia.

Schwoob ended up at Hamilton General, where it was discovered she had suffered a pulmonary embolism – a blockage of the pulmonary artery that leads to the lungs, caused by a blood clot.

The suit says that if Schwoob had been adequately warned of the increased risk of  experiencing an embolism, she would never have used the birth control pills.