1, pregnancy: to the day of menstruation, menstruation did not come, and there is an increase in the number of urination, appetite changes, vomiting, nausea, etc., such a situation are occurring after sexual intercourse, you can go to the hospital to do the early pregnancy check.

2, chronic diseases: some chronic wasting disease, often due to nutritional deficiencies and lead to delayed menstruation, common chronic hepatitis, tuberculosis, tumors, severe iron deficiency anemia.

3, mental factors: if there is a sudden mental overstress, grief, sorrow, anger, love and other abnormal emotions, often lead to delayed menstruation.

4, endocrine disorders: the most common clinical polycystic ovary syndrome, premature ovarian failure and so on.