My daughter is 12 and has had prolonged periods for the past 4 months. she is at 17 days and counting right now. her pediatrician said not to worry.?

Get second opinion.: On average, menstruation lasts 4-7 days. Though girls who have just started menstruating can have irregular cycles, it is not normal for periods to last 17 days. You might consider getting a second opinion to be sure nothing is wrong.

Second Opinion: Sometimes prolonged periods can happen and for a short time and then normalize. However excess bleeding for up to 17 days can cause significant blood loss and may be a sign of something else. To be certain i would see an ob/gyn for further evaluation.

Worry: Periods should last several days and taper. Periods that last too long or are too heavy may indicate a bleeding condition. Von willibrand's disease is one of these problems. Get a second opinion and get a blood count.