There are many reasons why menstruation is delayed for six days, such as normal phenomenon, pregnancy, endocrine disorders and so on. 1. Normal phenomenon: the normal menstrual cycle for women is 21-35 days, with an average of 28 days, so it is normal for women to have their menstruation 7 days early or 7 days late, usually without any discomfort. 2. Pregnancy: If a woman of childbearing age has a history of sexual intercourse and does not use any contraception, and her menstruation is delayed for more than a week, she needs to consider that it is caused by pregnancy. 3. Endocrine disorders: women with long-term dietary irregularities, overeating, long-term late night, mental stress, psychological pressure, etc., may lead to endocrine disorders, which can cause menstruation delayed for six days has not come. In addition, if a woman suffers from polycystic ovary syndrome and other diseases, it will also affect the endocrine, thus causing menstrual delay. In addition, other factors can also lead to this situation, such as taking drugs or the application of birth control devices, etc. If the phenomenon occurs for a long time, it is recommended that women go to the hospital in a timely manner to improve the examination, to identify the causes and follow the doctor’s instructions for targeted treatment.