©Pregnancy bliss 2008
Anemia and its causes
Hemoglobin (Hb) is the oxygen-
The short form 'Hb' is almost universally used to describe hemoglobin. So, if you encounter a tired junior doctor and he blurts out that, "You have a low Hb," what the poor chap means is that you are anemic.
The abbreviation "g/dl" that appears in front of the numbers is the form of measurement used for the hemoglobin level. It simply stands for grams per deciliter.
Causes of anemia in pregnancy
The production of hemoglobin and that of red blood cells (the latter by the bone marrow) is dependent upon the adequate supply of several "raw materials". The most important of these is iron.
Over 90% of those found to have anemia in pregnancy will have the problem because of iron deficiency.
Other possible causes of anemia in pregnancy
Vitamin B12 and/or folic acid deficiency could lead to anemia. They are a relatively uncommon cause in pregnancy but, when evidence of iron deficiency is lacking, these possible causes need to be investigated.
Anemia and Hemoglobinopathies
There are conditions which are collectively called "hemoglobinopathies". Affected people tend to have chronic anemia and pregnancy will tend to worsen the anemia.
The most common hemoglobinopathies are sickle cell disease and thalassemia. These conditions are discussed in detail in a dedicated section: "Thalassemia and sickle cell disease".
Iron deficiency is hardly ever a cause of anemia in these conditions. In fact, the tendency is to have iron overload. This is a direct result of multiple repeated transfusions, which are inevitable in most of these conditions. The transfusions will have started in childhood. These conditions are hereditary.
Pregnancy as a risk factor for anemia
The demand for iron goes up quite markedly in pregnancy. This is because there is an expansion of the blood volume to meet the new demands of pregnancy. The red cell mass may go up by as much as 25%. In addition to this, the fetus also takes its share. The fetus is totally dependent on the mother for everything, including iron.
Iron-deficiency anemia in Pregnancy
The requirements for iron that is absorbed from the diet roughly doubles in pregnancy. In fact, the more advanced the pregnancy gets, the higher the requirements for iron. If the diet has poor iron supplies, the iron stores in the body will be mobilized but will not be adequately replenished from the diet.
Eventually, the stores run empty and the hemoglobin levels start to fall. Some people conceive while already mildly anemic, with hardly any iron reserves. Such mothers will quickly become anemic, early in pregnancy.