Cytomegalovirus: What Pregnant Women Need to Know About CMV

First published December 2018
Updated July 2026

Cytomegalovirus: What Pregnant Women Need to Know About CMV

Cytomegalovirus (CMV) is a common virus that affects people of all ages. In fact, most people will be infected at some point in their life. For most adults and healthy children with a normal immune system, CMV causes only mild symptoms if any and doesn’t lead to lasting health problems. However, CMV can be more serious during pregnancy, since the virus can pass to an unborn baby and cause long-term health concerns. CMV infection acquired by the fetus is the most common nongenetic cause of hearing loss in childhood. In addition, it can cause developmental delays.

How CMV spreads:

CMV is spread through direct contact with bodily fluids such as saliva, urine, blood, semen, cervical or vaginal secretions, tears, and breast milk. Th most common mode of transmission is by sharing cups, water bottles, and eating utensils that are contaminated with CMV from a person who is shedding the virus in saliva. Breastmilk is also a common source of infants getting CMV.

Children, especially those in daycare or other group care, are a common source of infection as they mouth and share toys. Nearly one in three children in the U.S. become infected with CMV by age five, and the virus can remain active in their bodily fluids for months- even without symptoms. Because of this, parents and caregivers who spend time around young children may have an increased risk of exposure and subsequent infection.

Signs of CMV:

Most healthy people who become infected with CMV don’t even realize it. When symptoms do appear, they may resemble a mild illness with:

• Fever and fatigue
• Sore throat
• Swollen glands

For people with weakened immune systems, the infection may be more severe. Symptoms can include:

• Shortness of breath or cough
• Stomach pain, nausea, or diarrhea
• Blurry or lost vision
• Inflammation of the brain or spinal cord

CMV during pregnancy:

CMV can infect pregnant women for the first time during the pregnancy, or the virus can become active during the pregnancy from a past infection. In addition, the pregnant woman can get re-infected with a different strain of the virus than she was previously infected with. When CMV is active in a pregnant woman, the virus can cross the placenta and infect the developing baby. This is known as congenital CMV.

CMV in the newborn:

About 1 in 200 babies are born with congenital CMV infection, making it the leading infectious cause of birth defects in the U.S. While most babies do not show signs of infection or long-term health problems, some newborns may experience:

• Rash or jaundice
• Small head size
• Small for their gestational age
• Enlarged liver and/or spleen
• Brain abnormalities
• Vision problems
• Hearing loss (failed newborn hearing screen)

Even if a baby seems healthy at birth, some may also develop hearing loss, vision problems, and developmental delays later in childhood.

What can be done for your baby if infected with CMV:

There is no medicine that will kill and eliminate CMV from our body. However, babies who show symptoms, including hearing loss, from CMV may be treated with a medicine to quiet the virus for 6 months allowing better hearing and possibly developmental outcomes. All babies with congenital CMV infection need to have their hearing monitored through 6 years of age as well as their development to see if they should receive specific therapies.

Protecting yourself and your baby:

There is currently no vaccine to prevent CMV infection. The best protection during pregnancy is to reduce your risk of infection. Practical steps include:

• Wash your hands with soap and water after changing diapers or helping a child to use the toilet.
• Do not share food, utensils, cups, or pacifiers with a child.
• Limit saliva contact