Hi thanks for your question.
Usuall date for menstrual period of your girl friend is beteen 23rd and 24th of month that is what i can understand from question (23 24 mar).If it is so she has still 2 days to go for her periods.She has not still missed her periods.She is pregnant or not cannot be said with certainity at this stage.Ideally she should have bled after a tablet of unwanted 72.
i would suggest that she should wait for her due periods.If she misses her periods,go for pregnancy
test 10 days after missed periods to confirm or rule out pregnancy.
Hope this answers your question.