A new study has found that birth control methods that rely on a combination of the hormones estrogen and progestin may pose a higher risk of stroke and heart attacks compared to other hormonal methods. The study, conducted by scientists in Denmark, is the largest ever to study the risks of hormone-based birth control, according to a report from Reuters. It appears online in The New England Journal of Medicine.
Combination hormonal birth control includes the controversial Yaz and Yasmin birth control pills, as well as the NuvaRing vaginal ring. All three contraceptives have been named in scores of personal injury lawsuits alleging they caused young women to suffer blood clots, heart attacks and strokes. Last October, a study funded by the U.S. Food & Drug Administration involving some 8,000 women using various methods of hormonal birth control found that those taking birth control pills made with drospirenone, the type of progestin in Yaz and Yasmin, had an approximately 1.5-fold increase in the risk of blood clots compared to users of other hormonal contraceptives. The FDA has since required the manufactures of Yaz, Yasmin and similar pills to strengthen warnings about blood clots on the labels of their products.
The same FDA study found that NuvaRing raised the risk of blood clots, including deep vein thrombosis (DVT) and pulmonary embolism (PE), by 56% when compared to older birth control pills. The FDA study noted that combined hormonal contraceptives, including the etonogestrel/ethinyl estradiol vaginal ring, “potentially result in higher sustained exposure to estrogen and hence, increased thromboembolic risk.”
This new study out of Denmark, which also compared various types of hormonal contraception, was much larger than the FDA’s study. It analyzed data from of 1.7 million Danish women, age 15 to 49, none of whom had a history of heart disease. They were followed for 15 years, beginning in 1995. Women using a vaginal ring had about a two and a half higher chance of stroke than those not using hormonal contraception. Those taking low-dose estrogen birth control pills combined with various progestin, which would include Yaz and Yasmin, suffered heart attacks and strokes between 1.5 and 2 times more often than women not using hormonal contraception.
The risks were higher among women with diabetes and high blood pressure and those over age 35. The Heart attack risks doubled among those aged 40 to 44 compared to those aged 35 to 39, and increased by an additional one-third thereafter.