Progesterone injection is a kind of progestin, which can replenish the progesterone in the body after injection, and it works differently depending on the patient’s condition. If the patient is suffering from luteal insufficiency, progesterone injection can adjust the menstrual cycle of the woman, so that menstruation will come and go on time. In the case of luteal insufficiency and pre-eclampsia, or in the case of pregnancy with low progesterone levels and pre-eclampsia such as bleeding and abdominal pain, progesterone injection is mainly used to replenish progesterone, promote embryonic development and play a role in preserving the fetus. In case of delayed menstruation, intramuscular progesterone injection is usually required for 3-5 days at 20mg per day, and menstruation will come about a week after stopping the drug. Therefore, intramuscular injection of progesterone, can play a role in withdrawal bleeding.