Hi From your notes it is not clear when was your girl friend s last menstrual period? The first week and the last week of menstrual cycle are safe period. If you had sex during this time then there is no possibility of pregnancy. If you have had sex on any other day then you need to take I PILL if you wish to avoid pregnancy. I PILL is most effective when taken within 24 hours of intercourse. If I pill is taken in the second half of menstrual cycle it can delay the period. If period is delayed by more than a week then you need to do pregnancy test as there is a possibility of method failure ( I PILL is not 100% effective). I have an advise for you. If you wish to avoid pregnancy in future, your girl friend should consult doctor and start using regular contraception like birth control pills or intrauterine contraceptive devise as they are more effective than emergency contraception in preventing pregnancy. In addition please use barrier contraception like condom to protect yourself from sexually transmitted diseases. I hope I have answered to your satisfaction. If you have any further queries do contact me through Healthcare Magic.