Women’s menstrual period delayed three days do not come, the specific reasons are as follows: 1, pregnancy: if have sex without contraception, first need to rule out the possibility of pregnancy. 2, mental factors: if exclude pregnancy, may be related to the sudden and long-term mental depression, tension, worry, environmental changes, overwork, emotional changes, cold stimulation and other factors. 3, sports factors: dieting to lose weight, long-term strenuous exercise, or dance Ballet, modern dance and other training, also easily lead to delayed menstruation, do not come to menstruation. 4, disease factors: suffering from polycystic ovary syndrome, hyperprolactinemia, thyroid dysfunction, may also lead to delayed menstruation. Specifically what causes, but also need to go to the hospital for examination, for the cause of treatment.