Hi, Menstrual cycle is the process of changing in the uterus along with the release of eggs from the ovary with the help of hormones synthesized in the body. There are three phases follicular phase, ovulation and luteal phase. Progressive growth of eggs forms the follicular phase, ovulation is the process of release of eggs into the ampulla which travels through fallopian tube before fertilization and finally the luteal phase. If the egg is not fertilized, the progesterone level falls and the menstruation begins. Progesterone is the hormone that makes uterine lining thick for implantation of the fertilized egg, it also changes the consistency of the cervical mucus to prevent bacterial infection of the developing fetus and this hormones regulates the menstrual cycle. Meprate is the drug contains Medroxyprogesterone, man made hormonal precursor of progesterone which maintains the uterine lining on regular intake. If the drug is stopped, the hormonal level falls which results in shedding of the uterine lining. So, continue the drug till you wants to postpone menstruation. Visit a Gynecologist for further opinion. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Pradeepraj, General & Family Physician