Does plan b work on before and/or after ovulation if taken withing 24 hours?

Plan B: Plan b works anytime in the cycle. The sooner you take it after intercourse, the better - and certainly it has to be within 72 hours. Her just being 2 hours off on her pill is absolutely no big deal. Finally, remember Plan B does not protect you from std's, so use of a condom is always a good idea. If you plan to be sexually active, please make appointment with doc for contraception planning!