Menstruation deferred half month how to return a responsibility

Women's menstrual cycle in 21~35 days, menstrual cycle will be affected by diet, environment, drugs, endocrine, etc. appear early or delayed. If there is a history of sexual life, consider the possibility of pregnancy, can be judged by early pregnancy test paper. After excluding pregnancy, consider irregular menstruation caused, need to further blood test sex hormones, clear the cause.