MEDITERRANEAN ANEMIA AND PREGNANCY
Thalassemia syndromes, also known as Mediterranean anemia, are still frequently encountered in the regions including our city. In the presence of these disease states, pregnancy is important in two ways. The first is to follow up the pregnancy in terms of the mother in a mother who is sick or a carrier of the disease, and the second is to determine the status of the child to be born during the pregnancy of a woman who is not sick but her husband and herself are carriers. I would like to mention here the second case, which can be particularly difficult and confusing.
What is thalassemia or Mediterranean anemia?
It is a kind of blood disease. It is the expression of a genetic disorder in which the structure called hemoglobin, which is found in red blood cells, which is the main cells of the blood, is encoded, which undertakes the task of carrying oxygen. It can be divided into alpha and beta thalassemia. In addition to these, it would be appropriate to mention sickle cell anemia, another hemoglobin disorder that is not in the thalassemia class but is also common in our region.
Which couples are at risk?
Thalassemia syndromes and sickle cell anemia are autosomal recessive conditions. In other words, they are diseases caused by recessive genes. This means that a couple who are not sick but are both carriers have a 25% chance of having a baby.
How are risky couples identified?
Hemoglobin electrophoresis, which is a blood test performed by couples before marriage, which has been applied for a while, detects especially beta thalassemia and sickle cell anemia with high sensitivity. Alpha thalassemia, on the other hand, is less common but difficult to diagnose. It should be noted here that even if the electrophoresis result is normal, when anemia or microcytosis (low MCV in complete blood count) is detected in both spouses that cannot be explained by iron deficiency, the possibility of them being a carrier of occult alpha thalassemia should be kept in mind.
What is the way to be followed in risky situations?
As we mentioned, in cases where both the man and the woman are carriers, the risk of the baby to be born sick is 25%. Genetic examination for the suspected disease should be performed to detect sick babies. For this genetic research, fetal cells must be obtained. The two main methods used for this are CVS and amniocentesis. CVS can be applied at 10-12 weeks of pregnancy and amniocentesis after 15 weeks. As a result of genetic research of the cells obtained by one of these methods for the suspected disease, the disease can be determined with an accuracy rate of over 99%. An exceptional case is alpha thalassemia carrier. The genetic mutations that cause this situation are more than one, and in some cases, thalassemia carriers in the mother and father-to-be cannot be revealed by classical genetic research. In this case, called point mutation, if both the mother and father are clinically suspected of being a carrier of alpha thalassemia, even if the genetic examination is normal, the blood sample of the fetus may need to be examined by cordocentesis. Cordocentesis is the process of entering the umbilical cord of the baby in the womb with a needle under ultrasound guidance and taking the blood of the baby.
Preimplantation genetic diagnosis (PGD):
An alternative to the above-mentioned diagnostic methods for couples who are known to be carriers for a genetic disease is the method called PGD. It is based on genetic examination of embryos obtained by in vitro fertilization before they are transferred to the mother’s womb. One or two of the genetically sound embryos are transferred to the mother’s womb. Other intact embryos are frozen for future use.