Study Finds Yaz Ingredient Ups Blood Clot Risk

A new study has found that the type of progestin used in the Yaz birth control pill is associated with more blood clots than other forms of the hormone. The study is published in the British Medical Journal (BMJ).

Lawsuits have been filed around the U.S. by women who say they suffered serious side effects from Yaz.. The women involved in these lawsuits claim they experienced serious blood clots, including deep vein thrombosis and pulmonary embolism, as well as strokes. Yaz has also allegedly been associated with heart attacks and deaths in young women.

As we’ve reported previously, Yaz is made with a type of progestin called drospirenone. Drospirenone is known to carry some health risks not seen with other forms of the hormone. According to the U.S Food & Drug Administration (FDA), drospirenone can lead to hyperkalemia, a condition caused by excessive amounts of potassium in the blood, in high risk patients. This condition may result in potentially serious heart and health problem, and is especially dangerous for people who are obese, or who have diabetes or high blood pressure.

Since early 2004, the FDA has received over 50 reports of deaths in women who were taking Yaz and other drospirenone-containing contraceptives. Many of the reported deaths involved elevated potassium levels.

The BMJ study was conducted by researchers at the Leiden University Medical Centre in the Netherlands. It compared 1,524 patients on the pill and 1,760 who were not. There was a five fold increase in the number of women who suffered a dangerous type of blood clot called venous thrombosis in women taking the pill compared to those who weren’t. Among women who used oral contraceptives that contained drospirenone, there was a 6.3-fold increase in venous thrombosis.

The researchers found that low-estrogen oral contraceptives made with a type of progestin called levonorgestrel carried the lowest risk of blood clots.