Hemoglobin range is very important during Normal level of hemoglobin is 12 to 16 grams per deciliter for women during pregnancy. It is very important for hemoglobin to remain normal during pregnancy. During pregnancy, blood volume increases by 40 percent. Blood has two components, blood cells and plasma. Plasma is produced more in comparison to red blood cells, hence the level of hemoglobin decreases during pregnancy Visit Kolte Hospital for more details