How Does Cytomegalovirus Affect Pregnancy?

pregnant woman

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Cytomegalovirus (CMV) is a common virus that many of us haven’t heard of, but that most of us have had, or will contract at one point or another. The virus usually causes mild symptoms in healthy adults and children. CMV can be transmitted from a parent to their baby during pregnancy. While rare, in some cases, babies who are infected with CMV can experience birth defects or other lifelong health issues.

If you are pregnant and learning about CMV, it’s understandable that you might feel concerned. While CMV in pregnancy should be taken seriously, severe CMV infections in newborns rarely happen, and there are measures you can take to reduce the likelihood that you will become infected with CMV while pregnant.

Read on for what to know about CMV in general, how it affects pregnancy, and what you can do to reduce your risks.

What Is Cytomegalovirus (CMV)?

Cytomegalovirus (CMV) is a virus that most of us get in our lifetimes, sometimes without even knowing it, says Kecia Gaither, MD, a physician who is double-board certified in obstetrics and gynecology as well as maternal-fetal medicine.

“CMV (cytomegalovirus) is a common virus that infects individuals throughout the age spectrum,” she explains. “Most often people infected have no symptoms or are even aware that they have been infected.”

According to the Centers for Disease Control and Prevention (CDC), about one in three children will have had CMV by the time they are 5, and over 40% of adults have had CMV. Other sources say that as many as 50-80% of adults will have been infected with CMV by the time they reach their 40s. This means that if you are pregnant, it’s likely that you have become infected with CMV previously.

How CMV Spreads

CMV is in the same family of viruses as chickenpox, mononucleosis, and cold sores, says Laura Gibson, MD, an adult and pediatric infectious diseases specialist at the University of Massachusetts Medical School. “CMV passes between people easily and often has no symptoms in healthy people including children,” she explains.

As the CDC notes, the virus can spread in several different ways, including through direct contact with a person’s saliva (such as through kissing or sharing utensils), or through contact with urine (such as while changing a baby’s diaper). It can also be spread through sexual contact, and may spread through breastmilk. CMV can also be transmitted by a blood transfusion.

Like other similar viruses in the same family, CMV remains latent in your body after you’ve been infected, and can get reactivated and cause reinfections. It’s also possible to get reinfected with a different strain of CMV later in life.

Symptoms

Most people who have CMV experience mild symptoms, or may even be asymptomatic, says Dr. Gibson. This includes both children and adults. “Most people don’t know they’ve had CMV because they didn’t feel sick or had mild symptoms (like mono) or had the infection as a child,” she says.

If you do have symptoms, they may include a sore throat, fever, exhaustion, and swollen glands. However, for people with weakened immune systems, CMV can be more severe, and cause serious lung, liver, eye, or digestive system issues.

Most babies who contract CMV during pregnancy don’t have serious symptoms, but the concern is that some babies do. These may include conditions affecting a baby’s brain, lungs, liver, and growth. Long term issues such as hearing loss are another concern when it comes to CMV in babies.

Diagnosis and Treatment

Cases of CMV in adults are diagnosed by a blood test. In babies, saliva and urine tests are preferred. Again, most adults don’t realize they have CMV, or don’t have symptoms, so that majority of adults are never tested for CMV.

In most cases, there is no treatment needed when an adult or child has CMV. On the other hand, when it’s known that a baby has CMV at birth, antivirals may be offered.

How Cytomegalovirus Affects Pregnancy

For most healthy people, CMV remains dormant, so if you were previously infected with CMV, but do not currently have an active infection, there is likely nothing to be concerned about during pregnancy. (Keep in mind, though, that not all infections are symptomatic, so it’s not possible to know for sure if you are infected unless you are tested.)

However, it’s possible to get infected for the first time with CMV while you are pregnant, and it’s also possible that CMV gets reactivated in your body during pregnancy, causing a reinfection. Times that you are actively infected with CMV is when there is a concern of passing the infection on to your baby.

If you have an active infection of CMV, you could pass that infection to your baby through your placenta, explains Taylor Nelson, DO, infectious disease specialist at University of Missouri Health Care. “Once the mother is infected, the CMV virus is present in the organs and bloodstream,” she says. “The blood crosses the placenta and can infect the fetus. This is called vertical transmission.”

The biggest risk is if you currently have a new and active CMV infection, Dr. Nelson says. “If this is an initial infection for the mother, rather than a recurrent infection, the risk to the infant and potential severity of the congenital CMV infection is higher,” she clarifies.

Should You Get Tested for CMV in Pregnancy?

It’s not likely that you will be tested for CMV during pregnancy, says Dr. Gaither. “CMV screening isn't a common test done in pregnancy, but tell your health provider if you feel you have been exposed,” she advises. In that case, it will be important to verify whether you have contracted CMV or not.

There are other instances in which testing may be recommended, says Dr. Nelson. These may be in instances where the pregnant person has possible symptoms of CMV. Tests may also need to be done if the baby has fetal abnormalities that suggest a congenital CMV infection, Dr. Nelson adds.

How CMV Can Affect Babies

When a baby is infected with CMV during pregnancy, it is called congenital CMV. For the most part, congenital CMV is rare. Even when a baby gets CMV during pregnancy, it’s not always serious. According to the CDC, about one in every 200 babies will get congenital CMV. Even then, only about one in five babies will have a serious case.

Still, congenital CMV is something to be taken very seriously, because severe infections in babies are possible, and can have strong impacts.

“CMV is the most common of the ‘TORCH’ infections, which are serious infections that, if acquired by an unborn fetus in utero, are known to cause significant mortality and developmental abnormalities,” says Dr. Nelson.

Although some babies who are infected with CMV have no symptoms, a serious infection of congenital CMV can have several key symptoms, explains Dr. Gaither.

“Fetuses impacted by the infection display certain findings such as growth restriction, CNS abnormalities, hydrops, cardiac and liver abnormalities,” she says. Additionally, babies with CMV may be more likely to be born prematurely, have skin lesions at birth, have swollen lymph nodes, have pneumonia, and may born born at a low birth weight, Dr. Gaither adds.

Tragically, congenital CMV can also cause an infant to die in utero or to be stillborn, as the CDC reports.

Besides the immediate health issues that a serious case of congenital CMV presents with, babies born with CMV face potentially lifelong birth defects and disabilities. These may include intellectual disabilities, vision problems, seizures, trouble with coordination, muscle weakness, and hearing loss.

Hearing loss is one of the most common birth defects, and can occur whether or not a baby has other symptoms of congenital CMV. Signs of hearing loss from CMV can happen at birth, or at later points in life.

Treatment for Congenital CMV

The majority of babies born with congenital CMV don’t present with symptoms at birth, so neither their parents or their healthcare providers will be aware that they are infected, says Dr. Gibson. A minority of infected babies will have symptoms at birth; in rare cases, symptoms may be noticed on prenatal ultrasound, she says.

If it’s known that your baby has congenital CMV, there are a few limited treatment options, Dr. Gibson explains.

“Infants who have abnormalities identified in the first month of life can receive an antiviral medicine for six months that may stabilize or, less likely, improve some of those symptoms (especially hearing loss),” she describes. “However, no treatment eliminates the virus since it lives with each person for life, which means abnormalities can appear or get worse over time even if treatment is given.”

Preventing Congenital CMV

The best way to prevent serious congenital CMV is to not become newly infected with the virus during pregnancy. You can do this by practicing smart hygiene and virus prevention techniques.

“In many cases, the mother becomes infected due to contact with young children, often those who attend daycares,” explains Dr. Nelson. She advises that when you are pregnant, you take extra care to wash your hands after contact with young children, particularly after changing diapers or coming into contact with other bodily fluids.

CMV is spread through bodily fluids like saliva and urine, so you should avoid kissing anyone who might be infected, or sharing drinks and utensils. You should also make sure surfaces you touch are clean, and that you practice good hand hygiene.

What to Do If You’re Diagnosed With Cytomegalovirus

If you have signs of CMV or any virus during pregnancy, you should consult with your healthcare provider. If you are diagnosed with CMV, there will not likely be any treatment required, because most infections do not require treatment.

“If you are diagnosed with CMV during pregnancy, antiviral therapy is usually not needed, unless the disease is very severe,” says Dr. Nelson. However, she says, if you have a known infection of CMV, your baby will need to be monitored carefully.

“Routine prenatal care should be continued with frequent check ups with your OB/GYN doctor,” Dr. Nelson explains. “Monitoring of the fetus before birth and of the infant after birth for any signs of congenital CMV infection is essential.”

A Word From Verywell

Hearing about CMV during pregnancy and the scary impacts it can have on babies can be worrying. Try to keep in mind that most of us have had CMV at one time or another, and that CMV is usually only an issue if you are actively infected or reinfected during pregnancy. Even then, the chances of your baby getting a serious case of CMV is small.

Still, if you have questions about CMV, you should not hesitate to reach out to your healthcare provider. “Parents should not be worried, but instead be empowered to ask their doctor questions around CMV and be educated about ways they can reduce risk of getting their first or repeat CMV infection,” Dr. Gibson reminds us.

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10 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. CMV Fact Sheet for Pregnant Women and Parents.

  2. Centers for Disease Control and Prevention. About Cytomegalovirus (CMV).

  3. Centers for Disease Control and Prevention. About Cytomegalovirus (CMV).

  4. National Library of Medicine. Cytomegalovirus Infections.

  5. National Library of Medicine. Cytomegalovirus Infections.

  6. NSW Government. Cytomegalovirus (CMV) and pregnancy fact sheet.

  7. March of Dimes. Cytomegalovirus and Pregnancy.

  8. Centers for Disease Control and Prevention. Cytomegalovirus (CMV) and Congenital CMV Infection.

  9. American Academy of Pediatrics. Cytomegalovirus (CMV) Infections.

  10. Centers for Disease Control and Prevention. Babies Born with Congenital Cytomegalovirus (CMV).

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