13 year old daughter has HEAVY bleeding (bleeding through overnight pads in 2 hours). RBC 3.81, hemoglobin 11.2, hematocrit 32.5. Mild Anemia?

It happens. A likely cause would be a teens failure to release eggs in early menses which allows the estrogen dominated buildup of menses producing tissue.Periods can be heavy.At this age and with this presentation the worst it would be is a platelet or bleeding disorder like Von Willebrand disease which can remain silent until early menses. That would usually produce a greater drop in the blood count.