Will putting NuvaRing in the same day after intercourse prevent pregnancy?

It won't work as emergency contraception, but if you're putting it in no later than seven days after your last three-week-or-longer ring cycle, you're protected. If this is your first NuvaRing, get the morning after pill and start NuvaRing. Then use a back up method until you've used the ring correctly for seven days (14 if you used ullipristal for emergency contraception).