Hi! Thanks for your query. I understand your concern Regesterone (Norethisterone) is a progesterone hormone which may be used to delay periods. If your periods are regular you can start the tablet 3 days prior to the expected date and continue once daily as long as you desire, take the tablet preferably on the same time every day. Once the tablet is stopped, you will get your periods in a week s time. The bleeding might be slightly heavier than normal. Kindly remember that Regestrone does not act as a contraceptive when used in this way. It’s effectiveness at delaying periods also varies from woman to woman. Common side effects associated with its use are bloating, breast tenderness, nausea, headache and disturbances in mood and sex drive. Hope this answers your query. Kindly rate the answer, if you are convinced.