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A woman needs to undergo many tests when she is pregnant which can leave her slightly baffled. If you are pregnant, then perhaps you can relate to this. “Your doctor recommends you certain tests and you readily agree for it without really knowing what these tests are for and their purpose.” In the midst of all this, if the doctor asks you to carry out a test to rule out foetal anaemia, you will be confused even more. Don’t be confused, find out what is foetal anaemia, its causes, and how it is diagnosed.
What Is Foetal Anaemia?
The condition where the foetal circulatory system has a reduced number or quality of red blood cells is known as foetal anaemia. Red blood cells carry out the job of transporting oxygen to organs and cells in our body which means that foetal anaemia can cause several complications to the foetus. Foetal anaemia can be mild or severe depending on the condition. If the tests reveal severe anaemia, it will result in added pressure on the pumping of the foetal heart. The heart does this to compensate for the reduced red blood cells. This is why during foetal anaemia heart rate increases drastically, leading to foetal heart failure.
What Causes Foetal Anaemia
Foetal anaemia complications can occur when sufficient red blood cells are not produced by the foetus or when they are being destroyed faster than they are produced. Let us understand the causes that can lead to foetal anaemia:
1. Parvovirus Infection
This disease generally affects young children and toddlers, though adults too can be infected by parvovirus infection or the fifth disease as it is commonly known. Parvovirus B19 which affects the production of red blood cells is the cause of it. When the mother is infected by the fifth disease, the red blood cells developing in the bone marrow of the foetus get infected too. If the infection happens before the pregnancy enters the 20th week, it can prove to be fatal if the condition isn’t monitored closely.
2. Placenta Sharing
During a twin pregnancy, the placenta is shared between two fetuses. Due to reduced blood flow, it is most likely that one of the babies could suffer from foetal anaemia.
A rare tumour known as Sacrococcygeal Teratoma can affect the tailbone of the foetus. This causes the foetus to develop very large blood vessels and heart may be overworked due to extra pumping. Since the RBC formed in the bone marrow is insufficient, the body produces more RBC, thus affecting its quality. This causes foetal anaemia.
4. Maternal RBC Alloimmunization
This condition happens when the red blood cells of the mother and foetus are incompatible. The unborn baby carries some of the paternal blood antigens which the maternal antibodies do not recognize. Foetal anaemia is developed when the mother’s body develops antigens to attack the “foreign” bodies and destroys them.
5. Rh(D) Alloimmunization
When an Rh-positive baby is conceived by an Rh-negative mother, it causes Rh(D) alloimmunization, leading to foetal anaemia. Fortunately, this is rare nowadays as Rh(D) immune globulin shots are being administered well on time.
6. Metabolic or Genetic Disorder of the Foetus
When the foetus undergoes metabolic or genetic disorders like G-6 PD deficiency, Gaucher’s disease or Down’s Syndrome, foetal anaemia is observed.
Effects of Foetal Anaemia on the Unborn Baby
A foetus has a fully-developed and functional circulatory system just like adults. During foetal anaemia, the RBC (Red Blood Cells) count drops below normal. The main function of RBC is to carry oxygen to the organs and cells of the developing foetus. During foetal anaemia, the oxygen supply to the foetus is reduced. Severe anaemia can lead to the risk of heart failure. It is also possible that an abnormal volume of fluid is built up in the foetus’s body parts which is called hydrops. The organ functions of the foetus can be severely affected due to the heavy swelling. If this condition isn’t treated quickly, it can lead to the death of the child.
How a Foetus at the Risk of Foetal Anaemia Can Be Identified
Identification of a foetus that carries the risk of developing foetal anaemia is possible through tests and close monitoring of the mother and foetus. ISO-immunization screening is a standard part of regular prenatal tests nowadays. In case the tests are positive, the antibody is identified and the antibody level (titer) is determined through further tests. These tests can be repeated every 3-4 weeks.
Since not every maternal antibody leads to foetal anaemia, the risk level can be identified using a reference table. The father’s blood test is carried out to understand if the foetal RBC will produce the antigen. The foetus is at no risk if the test results are negative. If the pregnant woman is exposed to the parvovirus for the first time, she will need close monitoring for foetal anaemia signs.
How Is Foetal Anaemia Diagnosed
Diagnosis of foetal anaemia is done in the following ways:
1. Prenatal ultrasound
Foetal anaemia ultrasound is carried out to detect the signs of hydrops or foetal heart failure. The swelling of foetal tissues and fluid collection can lead to hydrops. Foetal heart failure is caused due to the reduced number of RBC and lack of oxygen, which makes the heart pump faster.
An amniocentesis test is carried out in order to obtain the amniotic fluid sample and check the level of bilirubin. It is carried out by inserting a needle through the mother’s abdomen to reach the amniotic sac. In this manner, a small fluid sample is obtained.
3. Foetal Blood sampling
Just like amniocentesis, a needle is inserted into the mother’s abdomen but directed into the foetal umbilical vein. This is done using ultrasound to visualize and guide the entire procedure. The foetal blood count is then checked by obtaining a small blood sample.
4. Maternal Blood Sample
By conducting a mother’s blood sample, it is possible to check if there are certain antibodies that can cause foetal anaemia.
How Is Foetal Anaemia Treated
Foetal Anaemia treatment includes frequent monitoring of the foetus and measuring the blood flow in the MCA (Middle Cerebral Artery). The doctor may also ask for a foetal blood sampling and transfusion in case of moderate or severe anaemia. During this procedure, using ultrasound visualization, compatible red blood cells are transferred into the umbilical vein. Depending upon the foetal condition, the doctor may ask for this procedure to be repeated once every 1-4 weeks.
Are There Any Effects of Foetal Anaemia After Birth
Post delivery, the baby may contract jaundice which could be severe. This happens when the baby’s bilirubin levels increase drastically. Jaundice will need to be carefully monitored by carrying out regular tests. In the case of mild jaundice, the baby’s health has to be observed carefully. Your doctor will speak to you about bringing down the bilirubin levels in the newborn if it is too high. Breastfeeding too can be done and the baby can remain and spend time with his parents in a normal manner. For any future pregnancies, the mother will have to be checked to avoid foetal anaemia.
Foetal anaemia can be difficult to handle for parents. Your baby will, as in most cases, be fine but it is important to remain in touch with your doctor. He will recommend ways to help you look after the newborn after delivery.
Also Read: What is Foetal Echocardiogram?