Normally, menstruation is five days, but this time only two days is not normal, and consider endocrine disorders, pregnancy and other related. 1. Endocrine disorders: if the patient has polycystic ovary syndrome, premature ovarian failure and other gynecological endocrine diseases, due to endocrine disorders and thus affect the ovarian ovulation function, which leads to irregular stripping of the endothelial lining and low menstrual flow and other manifestations. 2. Pregnancy: For patients with pregnancy-related diseases such as preeclampsia and ectopic pregnancy, irregular vaginal bleeding, abdominal pain and other discomforts due to adverse pregnancy are mistaken for menstruation. For women who usually have five days of menstruation but only two days this time, it is recommended that they go to the gynecology department of a regular hospital to improve the blood HCG, ultrasound and other related examinations, to clarify the cause of the disease and then actively treat under the guidance of the doctor.