Beta-thalassemia is an inherited blood disorder where your body doesn’t make enough beta-globin. Inherited means the condition is passed down to you from your parents.

Some people have the beta-thalassemia trait without developing the condition themselves. This is called being heterozygous.

You may be wondering how being heterozygous for the beta-thalassemia trait can affect pregnancy, and whether there are any special considerations to consider. We’ll address this topic and more below. Keep reading to learn more.

You inherit beta-thalassemia from your parents. To develop the condition, you must have two copies of a faulty gene. One copy comes from each parent. When you have two of the same gene copies, it’s called being homozygous.

Some people have one healthy copy and one faulty copy of the HBB gene involved in beta-thalassemia. This is referred to as being heterozygous.

If you’re heterozygous for this gene, you won’t develop beta-thalassemia. However, it’s possible that you may experience mild anemia symptoms.

Being heterozygous is also sometimes called “beta-thalassemia minor.” You may also see it referred to as “carrying the beta-thalassemia trait.”

Language matters

You’ll notice we use the term “women” in this article. While we realize this term may not match your gender, it’s the term used by the researchers whose data was cited. We try to be as specific as possible when reporting on research participants and clinical findings.

Unfortunately, the studies and surveys referenced in this article didn’t report data for or may not have included participants who are transgender, nonbinary, gender nonconforming, genderqueer, agender, or genderless.

If you’re pregnant and have the beta-thalassemia trait, you may have a higher risk of certain conditions. Researchers in a 2022 study compared pregnancy outcomes between pregnant women with thalassemia traits and pregnant women without them.

Pregnant women with the beta-thalassemia trait were more likely to have anemia during pregnancy. Researchers also noted that pregnancy-induced changes in the body could make existing anemia worse in heterozygous women.

The study also found that heterozygous pregnant women were more likely to have high blood pressure during pregnancy, which is associated with complications like preeclampsia. Indeed, a 2013 study involving pregnant women with thalassemia traits found an increased risk of preeclampsia.

However, the studies into how being heterozygous for the beta-thalassemia trait can impact pregnancy are inconsistent. For example, a 2011 study found no increased risk of preeclampsia in heterozygous pregnant women.

The research into how having the beta-thalassemia trait can impact your baby is also inconsistent. One 2015 study found that babies born to heterozygous women were more likely to have a low birth weight.

Researchers in a 2022 study also compared heterozygous women to women without the beta-thalassemia trait. It found that babies born to heterozygous women were more likely to have neonatal jaundice and significant weight loss.

However, a 2013 study aimed to determine whether babies of heterozygous women had an increased risk of things like low birth weight, growth restriction in the uterus, or stillbirth compared with babies whose mothers did not have the thalassemia trait. Researchers found no significant difference between the two groups.

One very important thing to know is that if you’re heterozygous for the beta-thalassemia trait, it’s possible that you can pass it on to your baby. If your partner doesn’t have the trait, your child could also just carry the trait as you do.

However, if your partner is also heterozygous or has beta-thalassemia themselves, your baby is at risk of having beta-thalassemia. While people’s outlook has improved in recent years, beta-thalassemia can still cause serious and possibly life threatening complications.

Most people who are heterozygous for the beta-thalassemia trait don’t experience any symptoms. However, some may have mild anemia symptoms, such as:

When you inherit a faulty copy of a gene from one of your parents, you’re considered to be heterozygous. In this case, it’s the gene for beta-globin.

Beta-globin is one of the two components of hemoglobin in your red blood cells. Hemoglobin is the oxygen-carrying molecule in these cells.

As we mentioned earlier, people carrying the beta-thalassemia trait typically have no symptoms. This is because having one healthy copy of the beta-globin gene allows for sufficient levels of beta-globin to be produced for your body’s needs.

If you’re heterozygous for beta-thalassemia, you may find out about it incidentally. It may be diagnosed after you visit your doctor for symptoms of anemia, or when routine blood testing shows that you have anemia.

A complete blood count is a blood test that can detect anemia. It measures the levels of different types of blood cells, including red blood cells. It also measures your hemoglobin levels as well as the size of your red blood cells.

However, this test cannot tell for certain whether you’re carrying the beta-thalassemia trait. To determine this, another test called hemoglobin electrophoresis is needed.

Hemoglobin electrophoresis looks at the different types of hemoglobin in a blood sample. The sample is placed in a special strip and an electric current is applied. This works to separate out the different types of hemoglobin.

After running the test, a doctor can observe and measure the different types of hemoglobin. People who are heterozygous for the beta-thalassemia trait will have a specific pattern of hemoglobin types.

Most people who are heterozygous for beta-thalassemia don’t need treatment. Your doctor will prescribe individualized care if any concerns arise during your pregnancy.

If your blood pressure gets high during your pregnancy, your doctor will want to continue to monitor you for signs of preeclampsia. They’ll also monitor the health of your baby as well.

Depending on the severity of the high blood pressure, it’s also possible your doctor may prescribe a medication to help lower it.

Most people who are heterozygous for beta-thalassemia do not have complications during pregnancy and deliver a healthy baby.

However, it’s important to consider the inheritance of the beta-thalassemia trait. This is because there’s a potential that your child could also inherit it as well.

Whether your partner is heterozygous for the beta-thalassemia trait or has beta-thalassemia themselves is important to consider. Let’s take a look at what this can mean:

  • Partner is also heterozygous: There’s a 25% chance your child will be born with beta-thalassemia. There’s also a 50% chance they will carry the trait and a 25% chance they won’t inherit it at all.
  • Partner has beta-thalassemia: There’s a 50% chance your child will be born with beta-thalassemia. There’s also a 50% chance they will carry the beta-thalassemia trait.
  • Partner doesn’t carry the beta-thalassemia trait: There’s a 50% chance your child will carry the trait and a 50% chance they won’t inherit it at all.

If you’re heterozygous for the beta-thalassemia trait, your doctor may suggest that your partner also be tested. If there’s a chance your child could be born with beta-thalassemia, genetic counseling will be recommended.

It’s also possible to test whether a developing fetus has beta-thalassemia. This is done using either chorionic villus sampling or amniocentesis.

Let’s look into the answers to some common questions about beta-thalassemia.

How common is beta-thalassemia?

Researchers estimate beta-thalassemia affects about 1 in 100,000 people within the general population. According to 2020 research, about 1.5% of the world’s population is heterozygous for the beta-thalassemia trait.

Are certain people more at risk of having beta-thalassemia or carrying the trait?

Yes. While anyone can have beta-thalassemia or carry the trait, it’s more common in some populations, including people who are from or have ancestry based in:

  • the Mediterranean, such as Greece, Cyprus, and Italy
  • the Middle East and North Africa, such as Iran, United Arab Emirates, and Egypt
  • South Asia, such as India, Pakistan, and Bangladesh
  • China
  • Southeast Asia, such as Thailand, Laos, and Malaysia

Are there other types of thalassemia?

Yes. In addition to beta-thalassemia, the other main type of thalassemia is alpha-thalassemia. It’s caused by inheriting two faulty genes for alpha hemoglobin, the other component of hemoglobin.

Are people who are heterozygous for beta-thalassemia more at risk of COVID-19?

Maybe. One 2021 pilot study found that being heterozygous for beta-thalassemia was associated with increased death from COVID-19. Overall, more research is needed.

Additionally, according to the Centers for Disease Control and Prevention (CDC), people with thalassemia have an increased risk of severe illness from COVID-19.

People who are heterozygous for the beta-thalassemia trait often don’t have symptoms. Some may have mild anemia.

Being heterozygous may be associated with high blood pressure during pregnancy and having a baby born with low birth weight. However, research on the outcomes of pregnancies in heterozygous people is overall inconsistent.

Typically, heterozygous people don’t need special treatment during pregnancy. However, a doctor may recommend testing and genetic counseling to determine the risk of your baby being born with beta-thalassemia.