Anemia during 32 week of pregnancy.

At the period of 28th week of pregnancy, hemoglobin detected 8.7gm/dl. Blood grp A neg. Doctor suggested to have Orofer s 100 mg injection once in a week, for 3 weeks. After 3 week of having the medication,  hemoglobin detected as 6.3 gm/ dl. Doctor suggested to test FERRITIN SERUM, detected as 716 ng/dl, (normal reference is 13 - 150 ng/ dl). She is having iron tablet named Speedral regularly in her pregnancy. Also Calonat D3 as calcium, Folvite as folic acid, Ecosprin (due to BP fluctuations  )are continuing from the beginning. Now my Gynecologist is not sure about why the hemoglobin range is dropping fast even after iron medication. He referred some Hematologist immediately. Please provide me suggestion on what to do. Feeling really helpless. What consequence will happen if the hemoglobin is not increased at the time of delivery? She is having low lying placenta and doctor suggested sec c operations.