As with adult females, the average length of menstrual flow for adolescent girls is 7 days or less. During her period, your daughter is likely to use between three and six pads or tampons per day. If her flow is significantly above this amount, you should contact your pediatrician.
For example, a heavy flow requiring changes of menstrual products every 1 to 2 hours is excessive, especially if the flow lasts longer than 7 days. Not only could this condition lead to anemia, light-headedness, or even fainting, it could also be a sign of polycystic ovarian syndrome, anorexia, tumors, other chronic illnesses, or side effects from medication, so have it checked out.
