Hello dear
I understand your concern
Your friend got period on 23th november.
Sex was done on 27th. Chance of
pregnancy is nil as sex was done on completely safe period of cycle.
Ovum is not released days after period and so no fertilization will occur.
But Unwanted 72 was taken and next day, it will help to prevent pregnancy.
But it cause
hormonal imbalance.
It may cause delay in period by 2-3 week and heavy bleeding can occur.
I would suggest to consult gynecologist for examination, undergo reproductive hormone analysis, USG scan.
Period can be induced by
progesterone pill.
Avoid
stress, take healthy diet, drink plenty of water, do regular exercise.
Hope this may help you
Contact further if follow up needed
Best regards
Dr. Sagar