Hello, I and my girlfriend engaged in foreplay but didn't have intercourse. There was some chance of pre ejaculation liquid entering her vagina so she took an unwanted 72 pill within 24 hours of the foreplay. She took the contraceptive pill on 22th and had her periods on 28th about 6-7 days later of consuming the pill. She had periods 28th of last month. Today is 28th and still she hasn't had her periods. Should I be concerned whether she is pregnant or not? Please give me a worthy advice on this matter. Thank you.