If the menstruation is more than 10 days early, it is often caused by the following reasons: 1. The luteal body shrinks early for some reasons, so the menstruation will be more than 10 days early, you can give timely treatment, such as oral progesterone after ovulation in the second half of the menstruation; 2. 3. taking oral contraceptive pills and having withdrawal bleeding after stopping the pills; 4. taking progesterone and having vaginal bleeding 3-7 days after stopping the pills, which may cause early menstruation. Therefore, in clinical practice, we combine the medical history with the corresponding examination and then make a preliminary diagnosis before giving treatment.