A recent study conducted by Danish researchers has concluded that newer birth control medications including Yaz and Yasmin may cause a greater risk of severe blood clots in women compared to older birth control medication. Published in the British Medical Journal, this study comes about as federal regulators have begun to closely examine the health risks associated with the pills.

The study suggests that newer, or “fourth generation,” birth control pills placed women at a greater risk for blood clots, compared to older pills. Researchers also noted that this increased risk is more likely to occur in women taking desogestrel and gestodene based birth control pills.

Women between the ages of 15 and 49 were studied. None of the women were pregnant between January 2001 and December 2009. In the study, 4,246 cases of what is known as thromboembolic events, or blood clots in the limbs, were found. About 25% of women suffered from pulmonary embolism, which is a blood clot which travels to the lungs, and 2% of women suffered blood clot related strokes.

Newer birth control pills that are desogestrel and gestodene based have been identified as having double the risk for blood clots compared to older birth control pills that are levonorgestrel based. Since women taking levonorgestrel based birth control pills have two times the risk for blood clotting than women not taking birth control at all, it is concluded then that newer birth control pills offer four times the risk of blood clotting than women not taking birth control.

The advisory board for the Food and Drug Administration (FDA) met on December 8th to discuss the benefits and risks associated with taking Yaz, Yasmin, and other popular birth control pills. It was determined that the benefits outweighed the risks.

Due to the increased risk caused by Yaz and Yasmin, thousands of Yaz lawsuits and Yasmin lawsuits have been filed against Bayer, maker of the two birth control pills, alleging that the company failed to properly warn about the increased risk associated with the birth control pills.