When you use NuvaRing or ANNOVERA correctly, it’s great at preventing pregnancy. But forgetting to put your ring in on time, taking certain medications, and other things may make it not work as well.
How effective is the birth control ring?
If you use it perfectly, the ring is 99% effective. But people aren’t perfect and it can be easy to make a mistake — so in reality the ring is about 91% effective. That means about 9 out of 100 ring users get pregnant each year.
The better you are about putting the ring in your vagina on schedule, the better it will work. But there’s a very small chance that you could still get pregnant, even if you always use the ring correctly.
If you want a method that’s even better at preventing pregnancy and more convenient, check out IUDs and the implant. They’re the best at preventing pregnancy and the easiest to use, since you don’t have to remember to do anything for it to work. But if you decide the ring is right for you, make sure you always stay on schedule so it works as well as possible.
What makes the ring less effective?
The main thing that makes the ring not work is not using it correctly.
That means you’re more likely to get pregnant if:
You don’t put your ring in on time every cycle.
Your NuvaRing ring is out of your vagina for more than 2 days (48 hours) in a row during the weeks when your ring should be in your vagina.
Your ANNOVERA ring is out of your vagina for more than 2 hours at a time, or at different times that add up to more than 2 hours total during the 21 days you’re supposed to have it in.
These medicines or supplements can also make NuvaRing and ANNOVERA not work as well:
• The antibiotics Rifampin, Rifampicin, and Rifamate (other antibiotics don’t make the ring less effective)
• The antifungal Griseofulvin (other antifungals don’t make the ring less effective)
• Certain HIV medicines
• Certain anti-seizure medicines (these are sometimes also used to treat psychiatric disorders like bipolar disorder)
• The herb St. John’s Wort
Your nurse or doctor can help you decide if there’s any reason the birth control ring won’t work well for you.