Progesterone is an important progesterone in the body, which is mainly secreted by the corpus luteum of the ovary. Insufficient progesterone levels are generally caused by ovarian corpus luteum insufficiency and endocrine disorders. The causes of ovarian corpus luteum insufficiency are mainly related to: 1. staying up late and not getting enough sleep; 2. smoking, drinking alcohol, drinking strong tea and coffee; 3. excessive dieting or excessive obesity; 4. suffering from some chronic diseases. Non-pregnancy tends to lead to abnormal menstruation, which is manifested by dripping menstruation. If the progesterone level is too low after pregnancy, the endometrial lining will be changed, which is not conducive to the development of the gestational sac and prone to miscarriage symptoms, requiring the use of exogenous progesterone for fetal preservation treatment.