How is the virus transmitted and what do antibodies mean?
Cytomegalovirus is transmitted through saliva, urine, breast milk, sexual contact and blood. Most often, pregnant women become infected from young children, who can shed the virus for months after a harmless cold. A blood test looks for two classes of antibodies. IgG indicates that there has already been an encounter with the virus, IgM appears with a recent infection or exacerbation. IgG avidity is determined separately: high avidity indicates a long-standing infection, low avidity indicates infection in recent months.
- IgG positive, IgM negative, high avidity - long-standing infection, low risk to the fetus
- IgM positive and low avidity - likely primary infection
- Both classes are negative - there is no immunity, prevention is important
- PCR of blood and urine helps clarify the activity of the virus
- One IgM result without avidity is not a diagnosis
Symptoms in an expectant mother
In most women, primary cytomegalovirus infection passes without obvious signs, and it is detected only by tests. Sometimes a picture appears similar to a lingering cold or mononucleosis: low temperature, weakness, sore throat, enlarged cervical lymph nodes, muscle aches. Since such complaints occur with dozens of other infections, a diagnosis cannot be made based on them—laboratory tests are needed.
- Low-grade fever for several days or weeks
- Severe fatigue
- Enlarged lymph nodes
- Sore throat and muscles
- Sometimes - changes in liver function tests
What risks does a child take?
The virus can pass through the placenta, but this does not always happen, and even when transmitted, most children are born without symptoms. Primary infection of the mother is of greatest importance, especially in the first half of pregnancy. Congenital cytomegalovirus infection can cause hearing loss, developmental delay, liver and retinal damage. Some manifestations are noticeable immediately, while others - primarily hearing impairment - may appear in the first years of life, which is why such children are observed longer than usual.
- The most common consequence is sensorineural hearing loss.
- Possible fetal growth restriction and low birth weight
- Less commonly - damage to the liver, spleen, retina
- Reactivation of a long-standing infection is much easier for the fetus
- After birth, the diagnosis is confirmed by PCR of urine or saliva in the first weeks of life
Survey and observation
If a recent infection is suspected, the doctor evaluates the timing based on antibody avidity and repeated tests, and may prescribe PCR of blood and urine. The condition of the fetus is monitored by ultrasound: they look at growth, the amount of amniotic fluid, the structure of the brain, and the size of the liver. In some complex cases, specialized centers discuss the study of amniotic fluid. The decision on the scope of the examination is made by the obstetrician-gynecologist together with the infectious disease specialist; you do not need to prescribe a panel of tests yourself.
- IgM and IgG antibodies to cytomegalovirus
- IgG avidity with positive IgM
- PCR of blood and urine for CMV
- Ultrasound of the fetus in dynamics
- Newborn hearing screening
What can be done for prevention
There is no vaccine for cytomegalovirus, but the risk of infection can really be reduced by simple household measures, especially if the family has a child under three years old or a woman works in a kindergarten. The main route of transmission is the saliva and urine of babies, so the main rule is hand hygiene and avoiding sharing utensils. Treatment with antiviral drugs during pregnancy is used to a limited extent and only as prescribed by a doctor; over-the-counter immunomodulators and dietary supplements do not protect against the virus.
- Wash your hands with soap after changing a diaper and feeding your baby
- Do not finish your child’s food and do not use his spoon or cup.
- Avoid kissing small children on the lips during pregnancy
- Clean toys and surfaces regularly
- All medications are only prescribed by an obstetrician-gynecologist
