Thalassemia in Pregnancy – An Overview

If you have any genetic disorders then it is quite likely that you may pass it on to your baby. Thalassemia is one such genetic disorder that you may transfer to your baby. Thalassemia in pregnancy may pose some serious complications. We shall discuss in detail how you may effectively manage your pregnancy if you have thalassemia.

What is Thalassemia?

Haemoglobin is an iron-rich protein that is found in our red blood cells. This protein is required to carry oxygen to various parts of our body and carry carbon dioxide which gets expelled from the lungs. Thalassemia is a genetic blood disorder that hampers the healthy production of haemoglobin by our body. This malfunction may cause serious cases of anaemia. These abnormal or deformed genes may get transferred from the parents to their children.

If you are pregnant, you should get in touch with your doctor to know more about thalassemia and pregnancy.

Types of Thalassemia

Haemoglobin in our blood comprises of matching protein chains, alpha chains and beta chains. The severity or the extent of complications associated with thalassemia varies, depending upon the number of mutated genes in these protein chains. The two main types of thalassemia are alpha and beta thalassemia.

1. Alpha thalassemia

    Alpha thalassemia occurs when there is gene mutation in the alpha protein chains. This may happen in the following ways:

• In a case where only one gene is affected or mutated: Not very substantial symptoms may be noticed.
• In a case where two genes are mutated: Mild anaemia may be seen, this condition is also known as thalassemia trait.
• In a case where three genes are mutated: It may lead to haemoglobin H or HbH disorder. This condition requires a regular blood transfusion to deal with the severe case of anaemia.
• In a case where all four genes are mutated: This may cause a life-threatening condition called alpha thalassemia major or Hb Bart’s syndrome. Babies who get affected with this genetic disorder rarely survive pregnancy or birth.

2. Beta thalassemia 

Beta thalassemia results from a gene mutation in the beta protein chains. This gene mutation may occur in following ways:

• In a case where one gene is mutated: This mutation may cause mild (thalassemia trait) as well as severe (thalassemia intermedia) cases of anaemia.
• In a case where the mutation occurs in both the genes: This mutation causes a serious condition known as beta thalassemia major or Cooley’s anaemia.

Sub Types 

Alpha and Beta thalassemia have been further categorized into two sub-categories:

Thalassemia Minor 

When the defected genes are inherited or transferred only from a single parent, then you may have a condition called thalassemia minor. People who have this condition are called the carrier of the disease. If you have this condition you may not have any health complications, but you may pass this defected gene to your baby.

Thalassemia Major

When the defected genes are inherited from both the parents, then it may lead to a life-threatening condition called beta thalassemia major. Thalassemia major causes serious complications in unborn babies. Most babies with alpha thalassemia major do not make it up to the pregnancy or birth. Beta thalassemia major is more common in babies and children than alpha thalassemia major.

What Causes Thalassemia in Pregnancy?

You may have thalassemia in pregnancy in following cases:

• You may inherit the defective gene from either of your parents.
• You may inherit the deformed genes from both your parents.
• You are more likely to inherit the defected genes if you belong to Asian, African, Middle Eastern or Mediterranean ethnicities.

How To Know If You Have Thalassemia?

Following points may help you know if you have thalassemia in pregnancy:

• You may already be on medication and treatment if you are suffering from a serious case of thalassemia.
• Your doctor may prescribe you blood tests during your first antenatal visit. These tests also include thalassemia test during pregnancy.
• You may get blood tests done for you and your partner before getting pregnant, to know if you or your partner has thalassemia.
• You may not know that you are suffering from thalassemia if you have alpha or beta minor thalassemia, your blood tests will help you determine it.

How To Know If Your Unborn Baby Has Thalassemia?

Thalassemia is an inherited disease, therefore if either you or your partner or both have thalassemia; there is a great possibility that your unborn baby may have it too.

In case if a single parent is a defective gene carrier, the chances of the unborn baby getting this gene are one in two. However, if both the parents have deformed genes carriers, then the baby has following chances of inheriting thalassemia:

• 25% chances that your baby has a severe case of thalassemia
• 25% chances that your baby is neither the carrier nor has any associated disease
• 50% chances that your baby is an asymptomatic carrier

In a case where you or your partner has thalassemia trait, following tests may be prescribed by your doctor for prenatal diagnosis of thalassemia:

• Your doctor may test your amniotic fluid after fifteen weeks of pregnancy. This test to check the amniotic fluid around your baby is known as amniocentesis.
• Your doctor may take a sample of your placenta at around eleven to fourteen weeks of pregnancy. The placenta is taken for DNA testing and this test is known as chorionic villus.
• Your doctor may do foetal blood sampling. This test may be done around eighteen to twenty-one weeks of pregnancy. The blood for the umbilical cord is taken for testing.

In a case where the unborn baby is diagnosed with alpha thalassemia major, there are very dim chances of survival. The doctor may recommend terminating the pregnancy as the baby may not sustain till delivery or birth.

How Does Thalassemia Affect Pregnancy and Baby’s Birth?

If you have thalassemia, you will be closely monitored by your midwife and doctor throughout your pregnancy. Your doctor may prescribe you folic acid as it would reduce the risk of your baby getting neural tube defects (spina bifida). The dosage may vary according to your condition.

In case you are beta thalassemia minor, your doctor may keep a regular tab on your iron levels in the body. You may be prescribed iron tablets to replenish the body’s iron requirement in pregnancy.

In case you are alpha thalassemia minor, you may have a mild or severe case of anaemia. You may require a blood transfusion to ward off anaemia.

In case you are beta thalassemia major, you may have severe complications in your pregnancy. You may require constant monitoring, medication and blood transfusion to sustain a healthy pregnancy.

Thalassemia may cause complications during birth. Therefore, it is recommended to go in for a hospital delivery. In case you are beta thalassemia major, which may affect your bones severely; vaginal delivery may become not possible and may require a c-section in the hospital.

Treatment 

The treatment options for thalassemia vary according to the severity and complexity of each case. However, the following are some of the common treatment options that may be suggested to you by your doctor:

• You may be prescribed supplements and medicines
• You may be advised for blood transfusion
• You may be recommended to go in for bone marrow transplant
• You may be advised for surgery (in severe cases) to remove your gallbladder or spleen

Will Your Baby Have Thalassemia? 

Here’s how you will know if your baby will have thalassemia or not:

1. If you or your spouse is thalassemia minor: There are equal chances of your baby either inheriting your defected genes or your baby may not inherit the defected genes at all. However, your baby will not be thalassemia major in this case.
2. If you and your spouse both are thalassemia minor: The chances are one in four, that your baby does not inherit the defected genes at all. Though your baby has the same amount of chances to be born with thalassemia major. However, the chances are one in two that your baby is born with thalassemia minor.

The above-mentioned possibilities remain same in each case of pregnancy, of the same couple. This means no matter how many kids the same couple has, the above-mentioned possibilities will apply in each case.

If your pregnancy tests show that you have thalassemia then you may have to undergo various other tests to determine the presence of this genetic disorder in your unborn child. In case it is established that your unborn baby is affected with thalassemia, your doctor may advise you to go in for genetic counselling. The counsellor will help you understand your situation and also recommend various treatment options that you may consider. The prompt and timely action will ward off any major complication that may arise because of this genetic disorder.