‘Two studies conducted in 2011 and 2012 reveal the risk of developing a serious blood clot among NuvaRing users is 11.4 and 8.3 per 10,000 women in a year, respectively. The NuvaRing’s label was updated in 2013 by the FDA with information about both studies.”
So at the higher end the risk is 0.14% of developing a blood clot.
EVERY package insert for any form of hormonal BC includes the warning about increased risk of thromboembolic disease. Every medicine is a trade off of effectiveness risk and side effects.
In addition, older women, overweight women and smokers all have increased risk of clots with hormone use. All of this spelled out in the package inserts for hormones.
That's what I'd call serious, especially since there are effective family planning methods that have zero risk.
As for the package insert warnings --- come on. Both the prescribing doctor and Merck have to do better than that.
Hormonal contraceptives ---- all of them, the OC, the patch, the injection, the vaginal insert or IUD --- harm women unnecessarily, and degrade the environment in ways we are just beginning to understand.
Assuming you're a man, maybe you would care more about the costs of hormonal contraceptives in the environment if you realized that they endanger your masculine primary and secondary sexual characteristics.