Amenorrhea means not menstruating, which is a common symptom of women. Women who are over 20 years old and still don't come to menstruation are called primary amenorrhea; After a normal menstrual cycle has been established, not menstruating for more than 3 months in a row is called secondary amenorrhea. Amenorrhea before puberty, after pregnancy, during lactation and after menopause is normal and not morbid. Abnormal uterine development, such as congenital absence of uterus, excessive curettage, endometrial tuberculosis, congenital absence of ovary, ovarian tissue destroyed by radiotherapy, or severe anemia, chronic nephritis, diabetes, hyperthyroidism or hypofunction of thyroid and adrenal gland; Environmental change, fright, fear, excessive tension, fatigue and other reasons can cause amenorrhea.