Is your blood Rh negative? Be aware of this during pregnancy (Rh Factor)

If you are a pregnant mother, or someone who is expecting a baby soon, one of the first tests your doctor will order is a blood test. This will check your blood type and something else very important. That is your Rh factor. You may have heard this term before. But many people don't have much idea what it means. What exactly is the Rh factor? Why is it so important during pregnancy? Don't worry, we will talk about it very simply and clearly.

Simply put, what is the Rh factor?

Okay, let's put it this way. Think of the red blood cells in your body as very small, round balls. Some people have a special type of protein attached to the surface, or outside, of these red blood cells. That protein is what we call the Rh factor , or Rhesus factor, in medicine.

This is something you inherit. That means you get it from your mother and father.

• Rh-positive: If you have the protein on the surface of your red blood cells, you are Rh-positive. In Sinhala, it means Rh positive. In Sri Lanka and the rest of the world, the majority of people, that is, about 85 out of 100, are Rh-positive.
• Rh-negative: If you don't have this protein on the surface of your red blood cells, you are Rh-negative. That means you are Rh negative.

Your blood type can be A, B, AB, or O. This Rh factor is associated with that blood type. For example, if your blood type is A and you are Rh-positive, your overall blood type is "A positive." If you are Rh-negative, it is "A negative."

Why is the Rh factor important during pregnancy? (Rh Incompatibility)

Here's what happens. We call this special condition Rh incompatibility , which occurs only when the mother is Rh-negative and the baby in the womb is Rh-positive .

Let's simplify this further. Think of your body as a country with a good defense army. Since you are Rh-negative, your country (body) does not have that Rh protein. Now, if the blood of the baby in your womb becomes Rh-positive, that means the baby has that protein in its red blood cells.

During pregnancy, the mother's and baby's blood usually don't mix directly. But sometimes, especially during childbirth, a very small amount of the baby's blood can enter the mother's bloodstream.

When this happens, the mother's defenses (the immune system) see the Rh protein in the baby's blood as an outside enemy, an invader. They think, "What's this new thing that's come into our body? This doesn't belong in our body," and they start making special weapons to fight against it. We call these weapons antibodies . This process is called Rh sensitization .

Situations where the baby's blood can mix with the mother's:

• During childbirth: This is the most common scenario. It can happen during a vaginal delivery or a cesarean section.
• Vaginal bleeding during pregnancy.
• An injury or accident to the stomach.
• Complications in early pregnancy, such as miscarriage or ectopic pregnancy.
• During special tests like amniocentesis.
• When the baby is in a breech position, the doctor tries to manually turn the baby during the ECV procedure.

Does this risk affect the first baby or the second baby?

This is very important. Usually, the first Rh-positive baby of an Rh-negative mother does not have any major problems.

The reason is, as we discussed earlier, the baby's blood is most likely to enter the mother's body during childbirth. Then, by the time the mother's body starts making those antibodies, the baby is already born. So the first baby won't be harmed.

But, the real problem begins during the next pregnancy.

Now the mother's body recognizes the Rh protein and prepares to make antibodies to fight it. If you carry an Rh-positive baby in your womb for the second time , the antibodies you made earlier, thinking, "Here comes the enemy again!", cross the placenta and begin to destroy the baby's red blood cells. It's like a war has started inside the baby.

This condition is called Rh disease . If left untreated, it can be very dangerous for the baby in the womb.

How do you diagnose this? What are the treatments?

Fortunately, diagnosing and treating this condition is very easy these days.

Diagnosis

As soon as you find out you're pregnant, your doctor will order a blood test to determine your exact blood type and Rh factor.

• If you are Rh-positive , there is no problem. You don't need to do anything else.
• If you are Rh-negative , another test will be done to see if your body has developed antibodies against the Rh protein.

Treatment: Anti-D vaccine

If you are Rh-negative and your body has not yet developed antibodies, doctors will give you a very simple but very important shot. This is usually called the Anti-D shot . The medical name is Rh immune globulin (RhIg) .

This vaccine is like a false message to your immune system. It completely stops your body from making those dangerous antibodies. This means that even if a little bit of your baby's blood gets into your body, your body won't recognize it as an enemy.

This vaccine is usually given when:

• Around 28 weeks of pregnancy: Every Rh-negative mother is given one vaccine at this time as a precaution.
• Within 72 hours of delivery: The baby's blood is tested and only if the baby is Rh-positive, the mother is given another injection. This is to protect the baby during the next pregnancy.
• In other cases: The doctor may also give this vaccine if there is bleeding during pregnancy, if there is a stomach accident, or if there is a miscarriage.

What problems can the baby have if left untreated?

Rh incompatibility does not affect the mother, but if left untreated, it can cause serious problems for the baby in the womb during the second or subsequent pregnancies.

The main problem is hemolytic anemia . Simply put, the baby's red blood cells are destroyed faster than they are produced. Red blood cells are what carry oxygen around the body. When they are destroyed, the baby can develop serious complications.

• Jaundice: When red blood cells break down, a yellow substance called bilirubin is produced. When this builds up, the baby's skin and eyes turn yellow. High levels can also damage the brain.
• Liver and Heart Failure: The baby's heart and liver have to work very hard to replace the red blood cells that are destroyed. This can cause these organs to enlarge and fail.
• Stillbirth: In the most severe cases, the baby can die in the womb due to anemia and heart failure.

But don't worry. With the development of the Anti-D vaccine, such severe conditions are very rare these days.

Rhesus factor, Rh factor, Rh negative, Rh positive, pregnancy, Anti-D vaccine, Rh incompatibility, Rh disease