How does waist acid not come menstruation to return a responsibility

In fact, this problem needs to be specifically analyzed, because menstruation has a cycle, generally 28~30 days is a menstrual cycle, to see whether everyone's menstruation is to the menstrual cramps time. If in the middle of the month, backache does not come to menstruation, this is a very normal thing. There is also a backache, to the time of this menstruation backache did not come menstruation, may not be due to this period of time too tired, or by the cold caused by menstruation delay, showing backache does not come menstruation some cases. If often this backache does not come menstruation, or is one or two menstrual cycles, three or four menstrual cycles are like this. Is it necessary to go to the hospital to do an examination to see if there is any delay in menstruation caused by some pelvic inflammation, and not to menstruate for this situation?