Generally, a progesterone shot of 40mg lasts for about 1 month, depending on each individual’s physical condition and response to progesterone. Progesterone is a progestin and is mainly used to increase the progesterone level in the patient’s body. If the progesterone level in a woman’s body is low in the non-pregnant state, it will lead to menstrual disorders or amenorrhea. 40mg of progesterone can last for about 1 month and there will be menstrual flow within 1 week after the injection. If the progesterone level in women’s body is low in early pregnancy, progesterone can be applied for fetus preservation treatment. This condition may require continuous medication for 7-10 days to have effect, and if the symptoms are not relieved, it is necessary to keep using the medication until after 12 weeks of pregnancy. It is recommended to use progesterone treatment under the guidance of a doctor, and the dosage should be strictly controlled, otherwise it will cause certain side effects to the body.