My menstruation is postponed all the time, what should check

Normal female menstrual cycle between 28-30 days, menstruation lasts 3-7 days or so, menstrual cycle ahead of schedule or push back a week are normal. If the phenomenon of long-term menstrual delay, should consider whether it is gynecological diseases or endocrine disorders caused. Suggestions: you can go to the hospital gynecology, sex hormones six and b ultrasound examination.