Progesterone is a progestin, used to regulate menstruation as well as clinical fertility preservation treatment, if you use progesterone, stop the drug for 10 days and still did not have menstruation is mostly considered to be pregnancy, endometrial lining thin, uterine adhesion, insufficient dose of the drug and other reasons. 1. Pregnancy: If you have had sexual intercourse without measures and have delayed menstruation, and have not had menstruation after taking progesterone, then it is considered to be caused by pregnancy. 2. Thin uterine lining: Generally speaking, if the uterine lining is not more than 7 millimeters to use progesterone capsules to promote menstruation, may not achieve the effect of menstruation, because the uterine lining has not reached the level of shedding. 3. Uterine adhesions: if after several uterine surgery or inflammation of the uterine cavity, caused by adhesions, then it may lead to menstrual blood flow, so the oral medication may not appear after the phenomenon of menstruation. 4. Insufficient drug dosage: Generally speaking, the use of progesterone capsules to promote menstruation is required to take oral medication for 7 to 10 days, after stopping the medication will come to menstruation, if the oral medication for a relatively short period of time, it is also easy to lead to menstruation does not come. If you find any abnormalities in menstruation, then it is recommended to consult a doctor in time for symptomatic treatment.