I want prescription about mensuration cycle m a 21 year old girl from last 3 month i didn't get periods i m worried .m not married?how it can treated?

Birth control pills: I am not completely clear about your question, but it sounds like you have not had a period in 3 months. If you have been sexually active then you need to take a pregnancy test. There are other causes for missed periods. If you are not pregnant then getting on birth control pills could help regulate your periods. See a doctor to make sure blood tests like thyroid are normal.