Cytomegalovirus (CMV) is a very common viral infection. Research shows that nearly 1 in 3 children in the United States is infected by age 5.[1] That means there's a good chance you've been infected with it in the past without even knowing it — and there's little risk it will have any impact on your pregnancy.
In fact, because the odds are so uncertain that any given baby will be impacted if a mom-to-be gets the virus, doctors don't routinely test for CMV during pregnancy. That said, it's important to let your doctor know if you think you've been infected with CMV while you're expecting, especially if you spend a lot of time with little kids. CMV can cause serious complications for babies after birth.
What is cytomegalovirus (CMV)?
Cytomegalovirus (CMV) is a common virus that's related to the herpes virus (which causes chickenpox and cold sores). It generally comes and goes with mild, if any, symptoms in healthy children and adults.
If a woman catches CMV during pregnancy, it can, in rare cases, lead to complications for an unborn baby. However, it's important to be monitored by your doctor, because for some babies, CMV can cause serious health problems.
How is cytomegalovirus (CMV) transmitted?
You can get sick with CMV if you come into prolonged contact with infected body fluid, including saliva, urine, mucus, blood, feces or semen. For example, you can contract the virus if you have sex with someone who's currently sick with CMV, or if the virus is on your hands and spreads to your mouth (one more reason that frequent hand-washing is so important).
People who have or work with little kids may be at a higher risk of CMV infection, since the virus is commonly found in the saliva and urine of young children (especially those between the ages of 1 and 3) and frequently spreads among toddlers at day care centers.
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CMV can be passed from a mom to baby any time during pregnancy through the placenta if the mother is infected with CMV for the first time, if she becomes infected with a different strain of CMV, or if the virus is "reactivated" because the immune system is compromised (due to a very serious but rare condition like HIV, for instance).
How common is cytomegalovirus (CMV)?
About 1 in 200 babies is born with congenital CMV (or a CMV infection at birth). Of the approximately 1 to 4% of people who get CMV during pregnancy, about 1 in 3 pass the infection on to their babies.
Most adults were infected with CMV as a child, which means about half of all pregnant women already have dormant CMV virus in their bodies from a previous infection. If you're among that group, the virus can be reactivated. But it's very unlikely that you'll pass the infection on to your baby — and even if you do, it's unlikely to cause any problems.
Even if you do pass CMV on to your baby during pregnancy, most babies born with the virus don't have health problems. In all, about 1 in 5 babies with congenital CMV have birth defects or other long-term problems.[2] Research suggests about 80 to 90% of babies with congenital CMV are asymptomatic at birth and have very low chances of long-term complications. The odds of long-term complications increase significantly in babies who are infected early on in pregnancy and in newborns who experience symptoms at birth.
What are the symptoms of cytomegalovirus (CMV)?
Although CMV often comes and goes without any obvious symptoms, you may experience the following signs of CMV:
- Fever that lasts a few days
- Constant, persistent fatigue
- Swollen glands
- Sore throat
These symptoms usually go away on their own within around three weeks.
Rarely, CMV can lead to mononucleosis (a condition caused by certain viruses that causes extreme fatigue among other symptoms).
What are the risks of cytomegalovirus (CMV) infection during pregnancy?
The majority of babies who are infected with CMV during pregnancy never show any signs of infection at birth. For the few who do, symptoms may include:[3]
- Seizures
- Small head size (microcephaly)
- Small size at birth
- Liver, spleen and lung problems
- Damaged retinas
A small percentage of babies with no symptoms at birth may show more serious effects later in life, including:
- Learning and motor disabilities
- Vision or hearing loss (CMV transmitted before birth is the leading cause of hearing loss in children)
- Seizures
Who is most at risk of cytomegalovirus (CMV)?
Women who have not been infected with CMV before pregnancy are most at risk (though it can be hard to know if that's you, since symptoms are so similar to other viral infections). The most serious problems from CMV infection are likely to occur earlier in pregnancy, particularly the first trimester — so it's an especially good idea to take extra hygiene precautions during that time.
People with weakened immune systems (from HIV or taking immunosuppressive drugs) are more likely to pass CMV on to their babies and may experience more serious symptoms that impact the stomach, intestines, esophagus, eyes, lungs and liver.
How is cytomegalovirus (CMV) treated?
There is currently no treatment for CMV infection during pregnancy. Antiviral medications are sometimes used to treat newborns diagnosed with CMV or people with compromised immune systems.
How can you avoid getting cytomegalovirus (CMV)?
Because there is the potential for serious birth defects with a CMV infection, it's smart to play it as safe as possible. As with any viral infection, your best defense is a good offense. If you have or are ever around small kids, be especially careful to try and avoid direct contact with their saliva or urine.
Try to be meticulous about the following:
- Wash your hands frequently and thoroughly with soap and water, especially after changing diapers or wiping noses
- Dispose of all diapers and tissues properly
- Carefully clean any surfaces or objects that come into contact with your child's saliva or urine
- Don't share glasses and utensils with anyone, particularly young children
- Resist nibbling on leftovers
- Consider avoiding kissing little kids on the mouth (opt for the forehead, for now)
- Keep in mind that CMV can spread through sex
What are the symptoms of cytomegalovirus (CMV) in new moms?
The symptoms of CMV in new moms are the same as during pregnancy. For most, that means having no symptoms at all. However, you may experience:
- Fever
- Fatigue
- Sore throat
- Muscle aches
What to do if you think you might have cytomegalovirus (CMV)
See your doctor if you have CMV symptoms, especially if you're at increased risk of CMV (e.g., you spend a lot of time with little kids and/or have a compromised immune system). Another reason to check in: CMV symptoms are similar to those of many other illnesses that require treatment during pregnancy, like the flu.
If your doctor thinks you might have CMV, they may do a blood test to see if you have CMV antibodies (a sign of infection). If you do have CMV, your baby can then be tested by amniocentesis or ultrasounds. While this can tell you about the baby's infection status, it can't tell you what the outcome of the infection will be.
If you tested positive for a CMV infection during pregnancy or if your baby shows signs of congenital CMV, your doctor will likely give your baby a test (usually of his urine or saliva) within two to three weeks of delivery to check for CMV antibodies. If the infection is confirmed, chances are still good that your baby may be asymptomatic and will not have long term consequences. Careful monitoring of growth and head size will likely be needed.
If your baby tests positive for CMV, your doctor may prescribe antivirals to minimize any potential impact of the infection. Your little one's hearing should also be regularly checked. And be sure to keep in touch with your child's doctor about any additional follow-ups.
CMV is present in the breast milk of infected patients, but should present no problem for a full-term infant. It can cause a premature or low birth weight baby to get sick, however. In those cases, speak to your child's pediatrician to determine how to breastfeed safely.
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