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From staying on top of your prenatal appointments to decorating the nursery, there’s so much to think about when you’re expecting a little one! Making sure that you stay healthy throughout your pregnancy is also important.

Part of this is trying to prevent infections that can spread to your developing baby. One infection, caused by a virus called CMV, can lead to potentially serious complications.

Below, we’ll break down what exactly CMV is, why it’s a risk during pregnancy, and many other important things to know. Keep reading to learn more.

CMV is a virus. Its full name is cytomegalovirus, but let’s just stick with CMV for short.

The first thing you need to know is that CMV is incredibly common. According to the Centers for Disease Control and Prevention (CDC), 1 in 3 children has contracted CMV by age 5. Over half of adults have the virus by age 40.

And once you have CMV, you have it for life. After the initial infection, the virus typically lies dormant (inactive) in your body.

So, how do you know if you have CMV? The answer is that many people don’t know.

CMV likes to fly under the radar and often doesn’t cause any symptoms. Due to this, most people who get CMV don’t even know that they have it. In some people, though, the infection can cause symptoms.

Generally speaking, there are three types of CMV infection:

  • Acute CMV. Some people with CMV will have a flu-like illness that causes symptoms like fever, fatigue, and aches and pains.
  • CMV in immunocompromised people. In people with a weakened immune system, CMV can lead to severe disease that can affect areas like the eye, brain, and digestive tract.
  • Congenital CMV. A developing baby can contract CMV while still in the womb. This can potentially lead to serious health or developmental concerns. About one in five babies born with congenital CMV will have long-term health problems.

That last bullet point probably caught your attention, so let’s break down exactly why CMV is a risk during pregnancy.

Remember that CMV is very common. The CDC estimates that almost half of pregnant people have already had CMV before their first pregnancy.

A small percentage of others, about 1 to 4 percent, will acquire the infection at some point during their pregnancy.

If you have CMV, it’s possible to pass the virus to your baby. This is because a virus that’s present in your blood can reach a developing baby through the placenta.

You’re more likely to pass CMV to your baby if you first get the virus during pregnancy. However, although it’s less common, transmission can still happen if you had CMV before your pregnancy.

CMV is a risk during pregnancy because serious complications can result when the virus is passed to a developing baby. In very severe situations, it can lead to pregnancy loss.

When a baby is born with CMV, it’s called congenital CMV. A congenital condition means one that’s present from birth. The CDC estimates that 1 in 200 babies are born with congenital CMV.

These babies can have a variety of short- and long-term health complications, including:

Most people who get CMV won’t have any symptoms. This is referred to as being asymptomatic. Because of this, most people who have CMV while pregnant won’t know that they have it.

Some people who get CMV during their pregnancy may experience symptoms of an acute infection. These can include:

Because the symptoms of acute CMV are often nonspecific, it’s easy to mistake them for another type of infection, such as the flu or infectious mononucleosis.

CMV is a type of herpesvirus. Scientists call it human herpesvirus-5 (HHV-5).

When you hear the word herpes virus, herpes simplex viruses 1 and 2 probably come immediately to mind. These are the viruses that cause oral and genital herpes.

However, the herpesvirus family is quite diverse. In addition to CMV and the herpes simplex viruses, it includes several other viruses that cause health conditions you may have heard of, including:

CMV is spread by coming into direct contact with body fluids that contain the virus, such as:

  • blood
  • urine
  • semen
  • vaginal fluids
  • saliva
  • tears
  • breast milk

You can get the virus if you come into direct contact with any of the body fluids listed above, then touch your nose, mouth, or eyes. CMV can also spread from person to person through:

  • pregnancy and labor
  • nursing
  • kissing
  • handling dirty diapers
  • sex
  • sharing items like toothbrushes, eating utensils, or cups
  • receiving a blood transfusion, organ transplant, or bone marrow transplant from someone with CMV

Laboratory tests can detect if you have CMV. Most of the time, these tests check whether you have CMV antibodies in your blood.

Even though tests are available, though, it’s unlikely that your doctor will test you for CMV while you’re pregnant.

Given everything we’ve discussed, this seems super counterintuitive. However, there are several reasons for this:

  • While a positive result tells you that you have CMV, it cannot predict if you’ll pass the virus to your baby or if they’ll develop any long-term health concerns.
  • The results from these tests can sometimes be hard to interpret. This means that it may be difficult to know if you had CMV recently or not.
  • While medications do exist to treat CMV in an adult or child, there’s not enough evidence to show that taking these medications prevents transmission to a developing baby.

While CMV testing isn’t the norm, there are definitely some situations where your doctor may recommend testing. These include if you believe that you’ve been exposed to CMV or if your doctor thinks that you have an acute CMV infection.

Now you may be wondering what can happen if CMV testing is recommended and you do test positive for CMV. The short answer is more testing.

Your doctor may suggest testing your developing baby for the virus through amniocentesis. This is when a healthcare professional collects and analyzes a sample of amnionic fluid. Your doctor may also request an ultrasound to check for signs of congenital CMV.

There’s no cure for CMV. Like all herpesviruses, once you’ve contracted CMV, you have it for life.

There’s not currently an approved treatment for CMV during pregnancy. While antiviral medications may manage the infection, they may not always prevent the transmission of the virus to a developing baby.

Researchers are studying which antiviral medications can safely prevent CMV transmission during pregnancy, and some results have been promising. For example, a small 2020 clinical trial found that the antiviral medication valaciclovir (Valtrex) may be safe and effective.

Babies born with signs of congenital CMV are treated with antiviral medications. These can lower their risk of developing long-term health complications.

Questions for your doctor or healthcare professional

Having concerns about CMV during pregnancy is typical. Know that you can always raise any questions or concerns that you may have to your doctor. Some examples to get you started include:

  • Can you tell me more about my risk of potentially passing CMV to my developing baby?
  • Should I receive testing for CMV? Why or why not?
  • What can I do to help lower my risk of exposure to CMV while I’m pregnant?
  • What symptoms indicate that I may have contracted CMV? When should I contact you about them?
  • After my child is born, what signs and symptoms may point to congenital CMV?
  • If my child is born with congenital CMV, how will it be treated? What specialists will be involved to help manage the short- and long-term effects of congenital CMV?

Many people get CMV when they’re still young. That’s why CMV is often found at high levels in the saliva and urine of babies and young children.

Direct contact with these fluids can increase your risk of getting CMV. Generally speaking, individuals who live or work with young children are at a higher risk of contracting CMV in this way.

With this knowledge in hand, you can take steps to avoid CMV while you’re pregnant by doing the following:

  • thoroughly washing your hands with soap and water after:
    • changing a child’s diaper
    • feeding a child
    • wiping a child’s eyes or nose
    • picking up a child’s toys
  • not sharing food, cups, or eating utensils with babies and young children
  • avoiding contact with saliva and tears when kissing children, trying to kiss them on the head or cheek instead

Additionally, since CMV can also be spread through sex, consider using a condom or other barrier method during sex if you know that your partner has CMV.

You’re more likely to pass CMV to your child if you first get the virus while you’re pregnant. This risk increases as your pregnancy progresses, reaching 40 to 70 percent by the third trimester.

When you get CMV is important for outlook. Contracting the virus early in a pregnancy, typically before 20 weeks, is associated with more severe effects.

Individuals who had acquired the virus before their pregnancy can also transmit the virus. However, the risk of passing CMV on is much lower in this situation, about 3 percent.

If you already have CMV, there are two scenarios where transmission is more likely to occur during pregnancy:

  • Reactivation. If the virus, which typically lies dormant within your body, reactivates during your pregnancy, viral particles can enter the bloodstream and reach the placenta.
  • Reinfection. You can also be reinfected with CMV if you contract a strain of CMV that’s different from the one that you already have.

However, about 10 percent do have health concerns at birth. Of these, 40 to 60 percent will have long-term health complications.

Prompt treatment with antiviral medications can help to improve the outlook for infants with congenital CMV.

You may still have some lingering questions about CMV in general. Below, we’ll aim to answer some of them.

What does CMV do to the body?

One of the hallmarks of herpesviruses is that the virus can become dormant like it’s sleeping. It is possible for CMV to reawaken, or reactivate. When this happens, viral particles can be temporarily present in your blood and other body fluids, and you may pass the virus to other individuals.

What are the long-term effects of CMV?

CMV doesn’t often cause problems for adults unless they are immunocompromised, are taking medications that suppress the immune system, or have HIV or cancer. However, babies born with congenital CMV can face long-term health effects like hearing loss, vision loss, and intellectual disabilities. CMV is the leading cause of non-genetic hearing loss at birth.

Is CMV a sexually transmitted infection (STI)?

Because it can be spread through sex, CMV can be considered an STD. However, keep in mind that CMV can also be transmitted in other ways as well.

Is CMV related to COVID-19?

No. CMV and SARS-CoV-2, the virus that causes COVID-19, are both viruses. But they’re not related. CMV is from the herpesvirus family and has DNA as its genetic material. SARS-CoV-2 is from the coronavirus family and has RNA as its genetic material. The viruses are transmitted in different ways and have different effects on the body.

CMV is a virus that many adults have by the time they reach middle age. During pregnancy, it can pass to a developing baby and lead to serious complications, particularly congenital CMV.

The risk of transmission is highest for people who first get the virus during pregnancy. However, individuals who acquired CMV before getting pregnant may also pass the virus to their baby, though this is less common.

Most people aren’t screened for CMV during pregnancy. Currently, there aren’t any treatments approved to prevent transmission during pregnancy.

If you believe you’ve been exposed to CMV or have symptoms of an acute CMV infection, checking in with your doctor or healthcare professional is a good idea. They can advise you on the next steps moving forward.