IUDs aren't foolproof. I know of someone that became pregnant while her ParaGard was installed. The risk is low, but it certainly happens. Even sterilization isn't 100% effective; conception can occur.
NuvaRing was an awful choice for me. It constantly popped out and caused infection in my case.
I went off of hormonal birth control because my neurologist informed me that I had an astronomical risk of having a stroke because I have experienced migraines with aura, I was overweight, and I was taking hormonal birth control. I decided that I really didn't want to die young, so I made the decision to cease that method after eight years of use. Additionally, the long-term effects (blood clots, cancer, etc) of taking hormones scares the crap out of me.