If menstruation is delayed and the test does not show pregnancy, the biggest reason may be endocrine disruption. It is possible that mental tension, work or study stress, poor sleep, or excessive dieting, or overweight may lead to endocrine disorders, which may lead to delayed menstruation. If menstruation is delayed for a short period of time, it can be observed temporarily. If it is delayed for more than a month, it is recommended to take blood to check the level of six female hormones to see if there is any problem with estrogen and progesterone. Gynecological ultrasound can be done to see if there is any abnormality in the uterine adnexa and endometrium, and if there are any gynecological diseases such as uterine fibroids, ovarian cysts, ovarian tumors, and excessive endometrial hyperplasia. These gynecological diseases may also cause delayed menstruation, and relevant tests can be done according to the specific situation.