What Doctors Want You to Know About the Common Virus Known as CMV

More than half of adults are infected by cytomegalovirus (CMV) by age 40, according to the Centres For Disease Control and Prevention. Yet it's very likely that you've never heard of this virus that's present in such a large portion of the population. While it rarely causes problems in otherwise healthy people, CMV can pose a risk to those who are immunocompromised, as well as people who are pregnant or are trying to become pregnant. Ahead, doctors explain what you need to know.

What Is Cytomegalovirus (CMV)?

CMV is a very common virus that, once transmitted, will remain in the infected individual for life — usually in a dormant state, Kiarra King, MD, FACOG, a board-certified ob-gyn in Illinois, told POPSUGAR. Healthy people with CMV may never experience symptoms or flare-ups of the virus, and are generally considered low-risk for complications.

Because of this, many people are unaware that they have CMV, explained Andrea Alexander, MD, FACOG, a board-certified ob-gyn in Texas and the author of Black Maternal Mortality: Our Fight Back. This is in part what allows the virus — which is transmitted through bodily fluids, such as saliva, breast milk, urine, blood, cervical secretions, and semen — to spread.

Dr. Alexander added that it's fairly rare for people to experience symptoms after the initial infection, but some may have a fever, fatigue, a sore throat, swollen glands, or muscle aches. If or when there's a secondary infection (which can occur if the virus reactivates), symptoms are typically less severe.

When Does CMV Become Potentially Harmful?

Those who are immunocompromised are at higher risk of "developing more severe symptoms and potential complications from CMV," Dr. King explained — including conditions affecting the eyes, lungs, liver, esophagus, stomach, and intestines. She noted that people who have had bone marrow, stem cell, or organ transplants, as well as those with HIV, are considered immunocompromised.

Similarly, those who are pregnant or are trying to become pregnant are also at greater risk. If CMV is contracted before or during pregnancy, it can be passed to the fetus in utero (an infection called congenital CMV), or to a baby during delivery or through breast milk, Michelle Rockwell, MD, a family medicine physician in Oklahoma, told POPSUGAR. She added that the earlier in the pregnancy the virus is contracted, the higher the risk of complications.

"The mother may get infected with CMV while she is pregnant and pass it along to the baby, or she could have had CMV before she was pregnant, have a reactivation of the virus while pregnant, and pass it along to the baby," Dr. Rockwell explained. If the infection occurs as a result of the virus reactivating, a baby's symptoms (if any) are usually very mild.

Dr. Alexander noted that contracting CMV for the first time during pregnancy is uncommon. She pointed to research which suggests that up to 1.3 percent of infants are born with congenital CMV, and of those cases, most are asymptomatic. It's estimated that just 10 to 15 percent of newborns show symptoms, which, according to Mayo Clinic, may include low birth weight, jaundice, pneumonia, and seizures, among others. However, even babies who appear healthy at birth are at risk for long-term developmental delays linked to CMV, the most common being hearing loss.

When Should You Talk to Your Doctor About CMV?

CMV has symptoms in common with a lot of other viruses, such as respiratory infections. For that reason, the experts POPSUGAR spoke with recommend talking to your doctor if you start to experience any of the symptoms listed here, especially if you're pregnant or work in a child-care or hospital setting where there's been an outbreak of CMV. Adults who are symptomatic can be diagnosed with a simple blood test.

To protect yourself against the virus, try to avoid direct and prolonged contact with bodily fluids, and wash your hands frequently, Dr. Rockwell added. If you're concerned about CMV or if you've tested positive for the virus, have a conversation with your doctor before becoming pregnant. While the virus is common, being diagnosed with CMV can be overwhelming, but your doctor will be there to help guide you every step of the way.