Our body has about 5-6 litres of blood. It accounts for about 7% of the total body weight. Blood contains cells and plasma. By volume, plasma constitutes about 54% and cells account for the rest. There are two major types of blood cells. They are white blood cells and red blood cells. There are five types of white blood cells called neutrophils, eosinophils, basophils, monocytes and lymphocytes. Red blood cells are also called erythrocytes. They contain a protein pigment/carrier protein called haemoglobin.
Haemoglobin transports oxygen from lungs to tissues. It also gives the red colour to blood. One haemoglobin molecule can transport four molecules of oxygen. Normal haemoglobin concentration varies according to age, physiological status; and in pregnant women, according to the period of gestation. Normal range for healthy non-pregnant adult female is between 12 mg/dl to 16 mg/dl. In the first trimester the normal range is between 11.6 – 13.9 mg/dl. It is 9.7 – 14.8 mg/dl and 9.5 – 15 mg/dl in the second and third trimester respectively. Anaemia in pregnancy means having a below normal haemoglobin level for the period of gestation.
What are the types of anaemia that occur in pregnancy?
There are three major types of anaemia that occur during pregnancy. They are iron-deficiency anaemia, folate-deficiency anaemia and vitamin B12-deficiency anaemia. Iron-deficiency anaemia occurs when the iron stores are inadequate. Iron is essential for the production of haemoglobin and leads to anaemia if deficient. Severe bleeding can also cause iron-deficiency anaemia. Folate and B12 are essential nutrients for DNA production. At bone marrow level, the blood cell production goes down if these are inadequate. In addition to anaemia, low folate leads to foetal nervous system defects.
Why does anaemia occur in pregnancy?
Poor dietary intake, poor absorption due to chronic bowel diseases, helminthic infections (worm infections), severe menstrual blood loss before getting pregnant and severe antepartum blood loss are a few known causes of anaemia in pregnancy. Multiple pregnancies and poor spacing between two pregnancies increase the risk of anaemia in pregnancy.
What are the symptoms of anaemia in pregnancy?
Breathlessness, poor exercise tolerance, dizziness, rapid heart rate, pale skin, clammy peripheries are a few common features of anaemia in pregnancy. Only severe anaemia causes symptoms because of effective compensatory mechanisms.
What are the risks of having anaemia during pregnancy?
Blood takes oxygen to the foetus via the umbilical cord and the placenta. When the amount of oxygen delivered to the foetus goes down the risk of having intra uterine growth retardation goes up. Your baby might end up having anaemia and developmental delays. If your anaemia is severe enough, you might need blood transfusion and then you will face all the risks of transfusion as well. During delivery you may lose a lot of blood. If you had anaemia to start with, body’s compensatory mechanisms may not be able to cope.
What can be done to prevent anaemia in pregnancy?
Safe practice is to do a full blood count before getting pregnant. Take treatment for any abnormalities. Take iron, folate and vitamin B12 tablets before getting pregnant. Doctors may prescribe oral iron therapy, intra venous iron therapy or blood transfusions as indicated during pregnancy. Continue the tablets at least six months post-partum.
By: Dr T.M.S.Sameera B. Madugalle MBBS (COL)