how long does the menstrual cycle last
It also prepares your body for pregnancy each month. A cycle is counted from the first day of 1 period to the first day of the next period. The average menstrual cycle is 28 days long. Cycles can range anywhere from 21 to 35 days in adults and from 21 to 45 days in young teens.The rise and fall of levels of hormones during the month control the menstrual cycle. Your periods become very irregular after having had regular, monthly cycles. 2  Your period occurs more often than every 21 days or less often than every 35 days. 3  You are bleeding for more than 7 days. 4  You are bleeding more heavily than usual or using more than 1 pad or tampon every 1 to 2 hours.