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Preliminary results from a large-scale study report funded by Merck (the manufacturer of NuvaRing) show that there are allegedly no difference in risk of venous thromboembolism (VTE—blood clots) between those women who use the contraceptive vaginal ring NuvaRing, and those who use combined oral contraceptives. These results conflict with another study recently published in the British Medical Journal on May 10, 2012, which independently found that women using the NuvaRing had a significantly higher risk of VTE and pulmonary embolism than those taking standard low-dose estrogen pills.

Studies Show Risk of VTE Higher with NuvaRing

In October 2011, the FDA released the results of a study showing that NuvaRing increased the risk of blood clots—including deep vein thrombosis and pulmonary embolism—by 56 percent when compared to older birth control pills. The researchers examined women age 10 to 55 years who were current users of the study contraceptives between 2001 and 2007.

According to preliminary results of a large-scale study funded by Merck, which was presented at the annual meeting of the American College of Obstetricians and Gynecologists (ACOG), researchers found no difference in risk for blood clots between women using the NuvaRing and those using combined oral contraceptives. For this study, named the "Transatlantic Active Surveillance on Cardiovascular Safety of NuvaRing," researchers recruited over 30,000 new users of either the hormonal vaginal ring or combined oral contraceptives, and followed them for two-to-four years. Using an MRI to determine cases of VTE, the authors concluded that rates for VTE were similar for both methods of contraceptives, and that the previously reported two-fold risk of VTE for NuvaRing users could be excluded. In examining the results of this study, there are some significant limitations that women should be aware of:

  • As of May 2012, the results were still considered preliminary, as they had not yet been accepted for publication in a peer-reviewed journal.
  • The study was funded by Merck & Co., which markets the NuvaRing.
  • There is a more recent BMJ study, which was not funded by Merck, which shows conflicting results that support the earlier FDA position.

The more recent May 2012 British Medical Journal study showed that non-oral contraceptives, including NuvaRing, created a higher risk of blood clots than did older birth control pills. Researchers gathered data on more than 1.6 million Danish women, aged 15–49, using methods of birth control other than the pill. They discovered that those using the NuvaRing had a 6.5 times greater risk of experiencing blood clots compared to women who didn't use any birth control at all, while women using birth control pills containing the hormone levonorgestrel have a risk only 3 times higher than those using no birth control.The researchers also stated that women using the vaginal ring were at a 90 percent higher risk of VTE than women taking combined oral contraceptives containing levonorgestrel, and concluded that women would be best advised to use standard birth control pills rather than patches or rings.

Comparing the Studies

What is clear from these studies and others is that NuvaRing clearly carries greater risks of blood clots over earlier generation birth control pills, which women should be warned of before being prescribed the NuvaRing. The companies who sell these products need to provide stronger warnings and insure that doctors and patients alike are informed of the risks associated with them so that women are not unnecessarily injured or killed like victims of the Ortho Evra Birth Control Patch, which have been widely covered by the media.

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