Pill and pregnancy question.

I'm not currently in this situation but I'm very curious. If you are on the pill, is there still a certain time when pregnancy would be more likely? Like if you took a pill late two days after you finish your period, could you get pregnant at that time or no because it's so close to your period? I guess what I'm asking is: does taking a pill late or missing a pill expose you to equal pregnancy risk no matter where you are in your cycle or would taking a pill late or missing a pill only really affect you if it was mid cycle?