Merck Manual

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Cytomegalovirus (CMV) Infection in Newborns

(Congenital Cytomegalovirus Infection; Perinatal Cytomegalovirus Infection)


Brenda L. Tesini

, MD, University of Rochester School of Medicine and Dentistry

Reviewed/Revised Oct 2022

Cytomegalovirus is a common virus Overview of Viral Infections A virus is composed of nucleic acid, either DNA or RNA, surrounded by a protein coat. It requires a living cell in which to multiply. A viral infection can lead to a spectrum of symptoms from... read more that usually causes few or no problems but can cause serious illness in infants who are infected before birth or around the time of birth.

  • Cytomegalovirus infection is caused by a virus.

  • Most newborns do not have symptoms, but some do depending on when they were infected.

  • Doctors diagnose the infection by identifying the virus in a sample of urine, saliva, blood, or tissue.

  • Newborns may develop neurologic problems such as hearing loss.

  • Handwashing can help prevent spread of the virus.

  • Cytomegalovirus infection cannot be cured, but some antivirals can limit the problems caused by infection.

Infection with cytomegalovirus (CMV) is very common. Blood tests show that 60 to 90% of adults have had a CMV infection at some time. The virus never goes completely away and remains dormant (inactive) in various tissues for life. Sometimes the virus reactivates.

Pregnant women who have never had CMV may acquire the infection easily through contact with infected people, most commonly young children. Women may also have active CMV because a previously dormant infection reactivated. In either case, the woman may not have any symptoms.

When a baby contracts CMV infection in the uterus, it is called congenital CMV infection. When a baby develops the infection immediately before, during, or shortly after birth, it is called perinatal CMV infection. CMV infection is the most common congenital viral infection.

A woman can pass the virus to her fetus during pregnancy if the virus crosses the placenta (the organ that provides nourishment to the fetus) and infects the fetus. Newborns may also become infected during passage through the birth canal, through breast milk containing the virus, or through a contaminated blood transfusion.

CMV infection may cause different problems in newborns depending on whether they were infected before or after birth.

Symptoms of CMV Infection in Newborns

Of newborns who are infected with CMV before birth, only about 10% have symptoms.

In newborns infected before birth, possible symptoms include

In newborns infected during or after birth, possible symptoms include

Some newborns have all of these symptoms.

Diagnosis of CMV Infection in Newborns

  • Testing of urine, saliva, or tissue samples

  • Polymerase chain reaction (PCR) test using urine, saliva, blood, or tissues

To diagnose CMV infection, doctors take samples of the newborn's urine, saliva, or tissues. The samples are sent to a laboratory so the organism causing the infection can be identified.

Doctors also do a PCR test Polymerase chain reaction (PCR) Genetic diagnostic technologies are scientific methods that are used to understand and evaluate an organism's genes. (See also Genes and Chromosomes.) Genes are segments of deoxyribonucleic... read more on samples of the newborn's urine, saliva, blood, or tissues. This laboratory technique, which produces many copies of a gene to make the gene easier to detect, can be used to detect the CMV virus in the DNA from the newborn.

Other tests are done to look for infection and inflammation and to determine the seriousness of the symptoms. Doctors may do other tests to rule out other infections present at birth that cause symptoms similar to CMV.

Prognosis for CMV Infection in Newborns

A significant percentage of CMV-infected newborns who have symptoms die. Most of the infants who have symptoms who survive will have some neurologic problems, including

About 5 to 15% of newborns who do not have symptoms eventually develop neurologic problems, but they are typically mild compared to the problems developed by newborns who have symptoms. Some degree of hearing loss is the most common.

Prevention of CMV Infection in Newborns

Pregnant women should try to limit their exposure to the virus. For example, because CMV infection is common among children attending day care centers and easily spread, pregnant women should always wash their hands thoroughly after exposure to urine and saliva from children in day care.

Treatment of CMV Infection in Newborns

  • Ganciclovir or valganciclovir for newborns who have symptoms

There is no cure for CMV infection.

Newborns should have repeated hearing tests during the first year of life.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Cytovene, Vitrasert, Zirgan
Valcyte, Valcyte Powder
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