A Tale of Two NuvaRing Studies With Vastly Different Outcomes

Washington, DCA recent study on NuvaRing side effects published in the British Medical Journal (BMJ) is at odds with results of another study funded by NuvaRing manufacturer Merck. One study claims the risk of NuvaRing blood clot is insignificant, while the other suggests a risk as high as 90 percent.

Guess which study was funded by the manufacturer of NuvaRing?

The Danish study, published earlier this month in the highly respected BMJ, found a meaningful risk for blood clots amongst women using NuvaRing Birth Control as opposed to women using more traditional forms of oral contraceptives. Industry watcher Tom Lamb, writing in his blog Drug Injury Watch (5/16/12), noted that the NuvaRing risk was markedly higher than that experienced by patients using combined oral contraceptives containing levonorgestrel.

The increased NuvaRing risk, writes Lamb, is comparable to the risk associated with combined oral contraceptives containing third and fourth generation progestogens and reflects the findings of a study undertaken by the US Food and Drug Administration (FDA) in 2011.

Blood clots can trigger risk of NuvaRing stroke and NuvaRing heart attack as well.

The Danish study was researched by Danish researchers Øjvind Lidegaard, Lars Hougaard Nielsen, Charlotte Wessel Skovlund, and Ellen Løkkegaard. Their findings, notes Lamb, conflict greatly with a large-scale study funded by Merck that found no difference in blood clot formation between the combination contraceptive vaginal ring, and combined oral contraceptives.

That study, dubbed Transatlantic Active Surveillance on Cardiovascular Safety of NuvaRing, noted that of the 34 incidents of blood clots occurring in the 66,489 women-years of contraceptive use (for the purposes of the study), the rate of VTE was 8.8 per 10,000 woman-years for the vaginal ring and 9.9 per 10,000 for combined oral contraceptives.

That difference, according to researchers presenting their findings at the annual meeting of the American Congress of Obstetricians and Gynecologists (formerly known as the American College of Obstetricians and Gynecologists) earlier this month, was not statistically significant.

Klaas Heinemann, MD, PhD, of the Center for Epidemiology and Health Research in Berlin, told colleagues at the 60th Annual Clinical Meeting May 7, "Venous thromboembolism [blood clot] rates are similar for NuvaRing and combined oral contraceptives," Heinemann said. "A twofold risk of venous thromboembolism for NuvaRing users compared to combined oral contraceptives can be excluded."

Any increased risk in blood clots can result in dangers for which a NuvaRing lawyer may help to foster a NuvaRing lawsuit. Skeptics will note the irony of an independent study sounding the alarm bells, v. a study funded by the NuvaRing manufacturer that interprets any increased risk as statistically insignificant.

Is interpretation worth a NuvaRing death?