Hi, thanks for your question.
Heavy menstrual bleeding in adolescent age can be caused by a number of things, however, the commonest reason is the immaturity of the hormone network which is responsible for ovulation and reproduction. At that age, most menstrual cycles are without ovulation. This causes
heavy periods. This should normalize in the next few cycles.
If the bleeding does not reduce in the next couple of cycles, other causes should be evaluated. These include hormone problems such as
thyroid issues and cushing syndrome, and bleeding disorders. Bleeding disorders would be suggestive if she also has nose bleeds and bleeding from the gums while brushing the teeth.
Observe for the next few cycles and continue to give her blood building drugs to prevent
anemia. If bleeding continues to be significant, revisit a gynecologist for evaluation.
I hope I have answered your question.
Warm regards.