How long does the nuvaring have to be refrigerated before its considered to "work"?

Never: The NuvaRing works upon placement in the vagina. The refrigeration extends the "usable life" of the ring. It is not required to keep if you are using them within the month. Let them warm to room temp by placing them in your pocket before removing the ring from the package. Less uncomfortable and slightly more pliable! no problem if you do keep them in the fridge, though!