can occur if the semen comes in contact with vagina even if it was not the actual penetration, but since your partner took an i-pill within 72 hours of the act, it has slimmed the chances of getting pregnant by 85 - 90 %. Due to the hormonal
effect of i pill
the periods can either come a week before or even a week later of the expected date. If periods are not coming after a week, my suggestion would be to do a pregnancy test which can be done even at home by the pregnancy kit. Thanks for posting and regards.