Hello Thanks for writing to us with your health query. In response to the emergency contraceptive pill, there is invariably some amount of withdrawal bleeding / spotting which occurs within a few days. What your girlfriend will probably experience is most possibly this withdrawal bleeding. Unprotected sex around midcycle means chances are high that she was ovulating. Emergency contraceptives are not very effective once ovulation has occurred. Now, the emergency contraceptive pill has the most common and undesirable side effect of causing menstrual irregularity. It would mostly alter her normal periods, either cause them to be early or late by a week or more days. Hence, she might not have her next period as expected, but it could also be earlier or later. Since you had unprotected sex, it is best to take a pregnancy test if she misses her normal period. Otherwise do not worry about this untimely bleeding, as it happens commonly after taking the emergency contraceptive pill. Please remember that emergency contraceptive pills are NOT a substitute for contraception. Taking them repeatedly and so casually will ultimately cause her more loss than gain. When taken again and again they lose efficacy. All the best Please feel free to discuss further.