Hi...
I'm 25. My periods are supposed to come 15 days back but still its not. I've not had any sexual course either. What could be the reason? What should I do to get the periods back on normal? This has not happened before.
Previously,I used to get the period regularly on time.
Appreciate your quick response.

Thanks!

It could be that you've been more emotionally or physically stressed, which can contribute to the delay in your cycle. Also, if you've just started birth control, or switch from one method to another, the change in hormone levels could have triggered the delay.
If you haven't had any sexual intercourse since your last period, then I wouldn't worry too much about it. Give yourself another week, if you haven't started by then, go see your doctor.

-m