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Blood clot risk info added to some birth control pills including Yaz

A packatge of the birth control pill Yaz is shown in this undated file photo.

April 11, 2012 12:00:00 AM PDT
Federal health officials are adding new labels to Yaz and other newer birth control pills emphasizing they may be more likely to cause blood clots than older contraceptive pills.

The new labeling will apply to Bayer's Yaz, its predecessor Yasmin and similar drugs that have the manmade hormone called drospirenone, which mimics the naturally occurring female hormone progesterone.

The Food and Drug Administration says the new labels will say that some studies have found as high as a threefold increase in the risk of blood clots in women taking pills containing drospirenone.

The risk of blood clots with either group of drugs is still very rare.

The Associated Press contributed to this report.