Nuva ring Q.

Hailee
Do you have to have the NUVARING in all the time besides when you take it out? I usually take it out during sex but last night I forgot to put it back in. So it's been 15 hours since its been in. What's the chance of becoming pregnant? My husband and I weren't really too worried if I do get pregnant. But we're just trying birth control to see how it does.