What would be a reason for low ferritin but normal hemoglobin?

It would be important for your doctor to look at the actual numbers of your iron studies and your complete blood count. If your ferritin level, this is the carrier molecule for iron in your body, is low the hemoglobin level is actually normal then at the present time,your body has enough iron to maintain a normal red blood cell count and hemoglobin level. A look at the entire profile would clarify

Ferritin is an indicator of iron stores. A person can have low iron stores and not be anemic. It would be prudent to take oral iron and multivitamin supplements to replenish you iron stores. Women lose iron in the blood lost during menstruation. Get HPV vaccine. Wish you good health!