If you miss a birth control pill or take one at the wrong time it increases the chances of becoming pregnant.
2 Additional Answers
If you miss a pill, it increases the likelihood of becoming pregnant. It's not that one missed or else late pill takes you to an instant zero percent outcome rate, but it decreases the protective effects.
You are likely to be pregnant if you miss one pill. This is because each pill works specifically for one day. It is therefore important to take each pill everyday at the same time so as to be on the safe side.