Typically a menstrual cycle can last for 28-35 days however, this is a general rule and may differ from people to people. Menstrual cycle is process of changes the body goes through in preparation of a fertilized egg. Every month one of the ovaries releases an egg which then travels through the fallopian tube to the uterus.
Meanwhile, due to the hormones released in the body, the uterus lining is prepared in anticipation of a fertilized egg. When the egg is not fertilized, the lining and the unfertilized egg passes through the cervix into the vagina and leaves the body. This shedding of blood every month (28-35 days) is called menstruating and the cycle that the body goes through is called the menstrual cycle. The cycle starts on the first day of the period and ends the day before the start of the next period.