Pregnancy and CMV (Cytomegalovirus)

Scanning electron micrograph of CMV
Scanning electron micrograph of CMV.

Ed White / The Image Bank / Getty Images

Cytomegalovirus (CMV) and pregnancy often go hand in hand. CMV is a common virus that rarely causes serious problems for healthy individuals—with an unfortunate exception being pregnant women and their unborn babies.

Although the majority of babies will not experience long-term complications, CMV can sometimes cause serious problems for unborn babies when moms without existing immunity are exposed to CMV in pregnancy.

More than half of pregnant women already have antibodies to CMV (meaning they have been previously exposed). Between 1% and 4% of expecting moms are exposed to CMV for the first time during pregnancy, and of these women, about a third will have babies born with CMV infection.

The majority of babies born with CMV will not experience long-term complications, but a small fraction may be severely affected. It is not known why some babies respond differently to CMV infection than others.

Risks of CMV Infection in Newborn Babies

About 40,000 babies are born each year with CMV infection. Around 90% of these babies do not have active CMV symptoms at birth. However, they may face an increased risk of hearing and visual disabilities later on, so follow-up screening may be recommended.

The 10% of infected babies that do have symptoms at birth have a more negative prognosis. Up to 20% of these babies may die due to complications from the infection, and up to 90% of survivors develop mental retardation, cerebral palsy, or other serious disabilities.

Signs and long-term effects of CMV in newborn babies include:

  • Developmental and motor delay
  • Enlarged liver and spleen (hepatosplenomegaly)
  • Hearing loss
  • Jaundice (yellowing of the skin or whites of the eyes)
  • Low birth weight
  • Microcephaly (small head)
  • Rash
  • Retinitis (damaged eye retina)
  • Seizures
  • Vision loss

CMV and Miscarriages

Some research shows that moms who are exposed to cytomegalovirus for the first time during pregnancy may have a higher risk of miscarriage, but the relationship of CMV to miscarriage is not completely clear at this point. The most serious risk seems to be that the baby could be born with a CMV infection.

Symptoms of CMV Infection in Pregnant Women

CMV infection frequently causes no symptoms in healthy adults, but some pregnant women may experience the following:

  • Flu-like symptoms
  • Mild fever
  • Sore throat
  • Swollen lymph nodes and glands

In rare cases, CMV can cause mononucleosis or hepatitis. If you have a weakened immune system, you can also have more serious symptoms that impact the eyes, lungs, liver, esophagus, stomach, and intestines.

Avoiding CMV Infection

Researchers are attempting to develop a vaccine against CMV, but none is currently available. The virus is transmitted via bodily fluids, including saliva and nasal secretions, and CMV is very common in daycare centers.

The CDC advises that the best way to prevent CMV infection is regular handwashing and using care in contact with young children.

Moms who work in daycare centers during pregnancy and don't know whether they are immune to CMV should use extra caution. Your doctor can run a blood test to tell you if you are already immune to CMV if you are concerned.

What to Do If You Think You Have CMV

It's a good idea to report any fever during pregnancy or flu-like symptoms during pregnancy to a physician. These symptoms can indicate a number of different infections, many of which can be dangerous, and your doctor will want to evaluate you to determine an appropriate treatment.

If CMV is confirmed as the cause of your symptoms, there is, unfortunately, no treatment available, but your doctor might want to perform extra monitoring on your baby to catch any complications as early as possible.

And although it can be scary to read about the what-ifs that can occur after CMV infection, it's important to remember that the majority of cases do not involve worst-case scenarios. Although there are no guarantees, the odds are that your baby will not suffer long-term complications.

If you have already given birth to a baby who had a serious case of congenital CMV infection, your future pregnancies will most likely not be affected. CMV infection usually results from a first-time exposure to CMV during pregnancy, and it is extremely rare for a subsequent pregnancy to be affected.

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Article Sources
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  1. March of Dimes. Cytomegalovirus in pregnancy. Updated November 2013.

  2. Cheeran MC, Lokensgard JR, Schleiss MR. Neuropathogenesis of congenital cytomegalovirus infection: Disease mechanisms and prospects for intervention. Clin Microbiol Rev. 2009;22(1):99-126. doi:10.1128/CMR.00023-08

  3. Centers for Disease Control and Prevention. Babies born with congenital cytomegalovirus (CMV). Updated April 28, 2020.

  4. Giakoumelou S, Wheelhouse N, Cuschieri K, Entrican G, Howie SE, Horne AW. The role of infection in miscarriageHum Reprod Update. 2016;22(1):116-133. doi:10.1093/humupd/dmv041

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