Just after taking progesterone less than an hour to menstruation the next day and then no considerations with the endometrium is not completely stripped, ovarian hypoperfusion, endometrial damage, such as sexual intercourse, but also need to rule out pregnancy. Progesterone can make the endometrium produce secretion phase response, usually in 1 week after stopping the drug endometrial stripping and appear menstrual vaginal bleeding, if the second day of menstruation and then no considerations with the endometrium is not completely stripped, ovarian hypoplasia, endometrial damage related: 1. The endometrium is not completely stripped: generally, progesterone should be taken for two weeks in order to make the endometrium produce sufficient secretion response, if not in accordance with the requirements of the medication may lead to incomplete stripping of the endometrium and the appearance of low menstrual flow. 2. Ovarian hypoplasia: For patients with ovarian hypoplasia, most of them have a combination of reduced estrogen levels, which affects the endometrial proliferation, and the endometrium is usually not thick, so there will be a small amount of menstruation, shortening of menstruation and other manifestations. 3. Damage to the endometrium: For patients who have frequent abortions, IUD removal, episiotomies and other uterine operations, due to the different degrees of damage to the endometrium during the operation, some patients may also experience low menstrual flow. 4. If there is sexual intercourse, it is also necessary to exclude whether the bleeding is caused by pregnancy-related. For the progesterone less than an hour to menstruation the next day and no patient, it is recommended to the regular hospital gynecology consultation, improve ultrasound and other related examinations, clear cause of the disease in the doctor’s guidance and active treatment.