Thalassemia is an inherited red blood cell disorder where there are fewer red blood cells in your circulation and less hemoglobin in them than usual. It is commonly seen in the Mediterranean region, Southeast Asia, Africa and India.
Hemoglobin is the protein in red blood cells that carries oxygen which is transported from your lungs to the rest of your body. The combination of fewer red blood cells and less hemoglobin within them will result in lower amounts of oxygen going to the rest of your body, the result of this will make you very fatiqued. Frequent blood transfusions will often be given if your situation becomes severe. This can cause iron overload in your body and chelating (a binding particle) treatment may be given to prevent this problem. An increased risk of infections and heart issues is often seen in people with severe thalassemia.
Thalassemia is caused by an inherited defect in your hemoglobin. The hemoglobin protein in your red blood cells is made up of alpha and beta parts that we call chains. If you have a genetic defect in the alpha chain you will have alpha thalassemia and if you have a genetic defect in the beta part you will have beta thalassemia.
The genetic defect for the two conditions is a little different. Four genes control the defect in the alpha chain. The amount of the genes affected will determine the severity of the condition.
If you only have one gene affected, you are not likely to be aware of it and you are often referred to as being a silent carrier. If you have two genes affected, you may have some mild symptoms and your condition is called alpha thalassemia trait. If you have 3 genes affected, your symptoms may often be severe and your condition is called Hemoglobin H disease. Having 4 affected genes, also known as alpha thalassemia major. An affected fetus will become too anemic to survive the pregnancy.
In contrast to alpha thalassemia, only 2 genes control the defect in the beta chain. If you have one defective gene, it is called beta thalassemia trait or beta thalassemia minor and you will usually only have minor symptoms, such as mild anemia. If you have 2 defective genes, it is called beta thalassemia major (or Cooley’s anemia) and you will often have more severe symptoms, such as failure to thrive(grow), problems feeding, as well as fever, diarrhea, and intestinal problems. These symptoms are not seen immediately after birth, because appearance is normal, but actually appears after the first few months of birth.
Thalassemia and its effect on pregnancy
During pregnancy, your baby will get a mixture of genes from both you and your partner and may end up with either more or less of the defective genes than either one of you.
If your baby has beta thalassemia, it won’t be noticed initially. Your baby will be protected while unborn and during the first few months of it life from the presence of fetal hemoglobin, a hemoglobin made by all babies’ blood cells in the beginning of its life. The fetal hemoglobin will act similar to normal beta hemoglobin and mask the soon-to-come abnormal hemoglobin.
It is only when the baby reaches about 3 months of age, that the fetal hemoglobin will be replaced by your baby’s innate hemoglobin and symptoms may then appear if your baby has inherited your beta thalassemic hemoglobin. If your baby ends up having beta thalassemia major it is, however on average life span of 17 years and generally die before their thirtieth birthday. The majority of deaths are caused by the heart complications of iron overload.
Alpha thalassemia on the other hand, will not be masked by the presence of fetal hemoglobin.
If your baby ends up having 3 or 4 defective alpha chain genes while in utero, it will become severely anemic which can cause a severe generalized swelling called hydrops. Growth restriction and stillbirth can then occur.
Do to the potential problems for your unborn baby with thalassemia (especially the alpha form), it is important to determine early if you carry the disease. Your health care provider will evaluate your blood cells early in your pregnancy. A complete blood count will often pick up an anemia. If the red blood cells are small, noted by a blood cell volume of less then 80, there is a suspicion for a thalassemia.
It will be important to make sure the anemia is not due to iron deficiency or sickle cell disease. The next step is to do an iron storage test and a maternal hemoglobin analysis to look for abnormal hemoglobin. Doing a complete blood count on the father of the baby is often recommended. If both of you carry one or more of the alpha or beta thalassemia genes, do speak to a genetic counselor regarding additional testing and how to plan the rest of your pregnancy.