Physiological period only half a day is not normal, may be endocrine disorders or reproductive organs organic lesions and other causes, but also to exclude pregnancy complications, such as miscarriage or ectopic pregnancy. 1. Endocrine dysfunction, due to excessive stress, emotional fluctuations lead to hormone secretion disorders in the body, endometrial stripping is too small, which will cause low menstrual flow. 2. Thinning of the uterine lining, due to multiple abortions or a history of uterine operations leading to thinning of the uterine lining, even if the body’s hormone levels are normal, when the hormone retreats, there is not enough endometrial stripping bleeding. 3. Inflammatory diseases of the reproductive tract, such as endometritis or tuberculosis causing destruction of the endometrium and incomplete stripping, leading to decreased menstrual flow. 4. Miscarriage or ectopic pregnancy, fertile women with irregular vaginal bleeding must rule out the possibility of pregnancy, miscarriage or ectopic pregnancy can also occur with a small amount of vaginal bleeding, some of the vaginal bleeding with abdominal pain that occurs around 7 weeks after the menopause can be mistaken for menstruation. It is recommended that women in their childbearing years keep a record of their menstrual periods, consult a medical professional if they have stopped menstruating or have a short physiological period, and cooperate with the doctor to do the appropriate auxiliary examination and timely treatment of the primary disease.