Under what circumstances can menstruation be delayed

Usually in the long-term stay up late, spicy greasy diet, mental stress and other circumstances, there will be menstrual delay phenomenon, but if accompanied by ovarian cyst, polycystic ovary syndrome and other diseases, there will also be menstrual delay phenomenon; usually should ensure balanced diet nutrition, adequate sleep, and to the regular hospital obstetrics and gynecology department to do B-ultrasound, sex hormone six examinations.