Menstruation comes back after half a month, that is to say, menstruation comes once every twenty days or so. This situation is most commonly caused by luteal insufficiency and endocrine disorders, such as frequent late nights, mental tension, stress, leading to endocrine disorders; or emotional fluctuations, which can lead to endocrine disorders; or clinically eat certain drugs, such as blood-activating drugs, can also make menstruation earlier. In this case, it is recommended to go for ultrasound examination, the main purpose is to exclude whether there are organic lesions, such as whether there are submucosal uterine fibroids, whether there are endometrial polyps and so on. If these are present, they may lead to early menstruation. Also, blood should be drawn to check the sex hormone six to see if it is due to endocrine disorders. If it is luteal insufficiency, progesterone can be supplemented in the second half of menstruation, for example, starting on the 17th day of menstruation, oral progesterone gelatin pills once a day, take 2 pills at a time, and take oral pills for 10 consecutive days, and menstruation will come in 3-7 days after stopping the pills.