The NuvaRing birth control device was first approved by the FDA in 2001. In October 2011, the FDA released a drug safety study report indicating the NuvaRing was associated with a significantly higher risk of developing deep vein thrombosis and pulmonary embolisms than standard low-dose estrogen birth control pills. Now, according to new results published this month in the British Medical Journal, women using the vaginal ring are at a significantly higher risk for venous thrombosis compared to those taking earlier generation oral contraceptive birth control.

All hormonal contraceptions come with some risk of blood clots, which can lead to other complications like deep vein thrombosis and even life-threatening pulmonary embolism and stroke. Danish researchers, however, studied pregnant women ages 15-49 who were free of any prior thrombotic disease, between 2001 and 2010, and discovered that women who use vaginal rings like the NuvaRing for contraception have a 6.5 times increased risk of confirmed venous thrombosis compared with non-users of hormonal contraception.

The researchers further noted that “the vaginal ring conferred a 90% higher risk of venous thrombosis than did combined oral contraceptives containing levonorgestrel, bringing the risk to the same level as that of combined oral contraceptives with third and fourth generation progestogens”—such as Yaz and Yasmin. The researchers concluded that, "women are generally advised to use combined oral contraceptives with levonorgestrel or norgestimate, rather than to use transdermal patches or vaginal rings."