Birth control patch raises blood clot risk: Health Canada

Using the birth control patch Evra may increase the risk of developing blood clots in the legs and lungs, Health Canada warned Thursday.

The patch sold in the U.S., which contains more of the ingredient ethinyl estradiol than those sold in Canada, has been linked to a higher risk of blood clots than oral birth control pills, the maker of the patch said.

However, both may carry the same risk of side-effects, Health Canada said.

"We're taking the precaution of giving people an additional heads-up that there's a risk of blood clots with the product," said Health Canada spokesperson Alastair Sinclair.

Women who are obese are at particularly high risk of blood clots, the safety alert said.

Canadian labels for Evra say it is important to stop using the medication at the earliest sign of blood clots.

The U.S. Food and Drug Administration released a similar warning in September.