Vacation means menstruation. Delayed menstruation for 8 days is not necessarily a disease, but may be caused by physiological factors such as pregnancy, late nights, or diseases such as polycystic ovary syndrome or hyperthyroidism. 1. Physiological factors: For women of childbearing age who are sexually active, an 8-day delay in menstruation needs to be considered as a possible pregnancy. Secondly, if there are recent bad habits such as staying up late, excessive mental stress, excessive weight loss, etc., it can also lead to delayed menstruation. 2. Polycystic Ovary Syndrome: The cause of this disease is still unclear, and studies have shown that it may be related to heredity, as well as over-nutrition, poor lifestyle and other factors. Typical symptoms are menstrual disorders, which may be manifested as delayed menstruation for 8 days. 3. Hyperthyroidism: The underlying causes of this disease include diffuse toxic goiter and thyroid nodules. For women, there will be changes in the menstrual cycle, which can be manifested as a prolonged menstrual cycle, so the patient may experience a delay in menstruation for 8 days. 4. Other: In addition, clinically, we also need to consider the early onset of ovarian insufficiency and other diseases, or the use of progesterone, dydrogesterone and other progesterone drugs caused by delayed menstruation. It is recommended that people who have delayed menstruation for 8 days should go to the hospital to improve the relevant examinations and clarify the specific causes.