After taking progesterone, most of them will have menstruation 3-7 days after stopping the medicine, and some will not have menstruation. In clinical practice, the following reasons are common: first, due to premature ovarian failure, the level of estrogen in the body decreases, so the endometrium will not change in response to the stimulation of progesterone, so it will not menstruate. The second, due to pregnancy, if pregnant after the progesterone will play a role in tranquilizing the fetus. Because progesterone is a progestin, after pregnancy, the endometrium will undergo metamorphic changes, progestin on the endometrium will not cause withdrawal bleeding after stopping the drug, so after taking progesterone, there are individuals who will not have menstruation because of certain problems.