In the course of taking progesterone orally and having a period, it is recommended to stop the drug immediately and just let the period come. This situation is most likely caused by taking progesterone at the wrong time, for example, when the endometrium has become significantly thickened in the second half of the menstrual period under the effect of progesterone and is not sensitive to exogenous progesterone. Therefore, if progesterone is taken at this time, the original thickening of the endometrium will begin to change with the ovarian cycle, and when the corpus luteum atrophies, menstruation will occur. Therefore, if you get a period in the middle of taking progesterone, just stop the medication immediately.