hello, Beside pregnancy, there are several reasons of late period like ovarian cyst, hormonal imbalance, stress, over wt, thyroid problem, high prolactin, irregular diet pattern etc. One pelvic USG and hormone tests are required to pinpoint the diagnosis if late period continues in next cycles. Primolut-N is given to induce period with correction of progesterone deficiency. You will get a withdrawal bleeding within 5 to 7 days of stopping medication. Take balanced diet, avoid mental stress, control body weight and always maintain a healthy lifestyle. Good luck.