We old veterans know that menstruation is the shedding of the lining of the uterus. For some of us it seems like we've known this forever. For the newbies among us however, here is the scoop on menstruation.
Not all periods are the same, though most women will have their own kind of "normal" and don't usually depart too far from it. The average menstrual cycle is 28 days, hence the "monthly" scenario. In actuality though a woman's menstrual cycle can regularly be shorter or longer. Or for some, there may be no regularity to speak of. Most periods last between three and seven days.
When something is different from our personal normal ... we should pay attention.
Dr. Franklin Loffer is executive vice president and medical director of AAGL, which was formerly the American Association of Gynecologic Laparoscopists. "Any period issue that is out of the ordinary for you warrants a call to your doctor, especially if it makes you uncomfortable or keeps you from doing your normal activities. 'If a woman feels that it's interfering with her lifestyle, then she needs to address it,' Loffer says."
http://women.webmd.com/features/when-your-period-signals-problem?ecd=wnl_wmh_070510