I. Epidemiology of congenital cytomegalovirus infection Congenital CMV infection occurs worldwide, with a prevalence of 0.6% in developed countries. The rate of congenital CMV infection (not necessarily congenital CMV disease) is proportional to the rate of CMV seropositivity in women of childbearing age. In areas with high CMV seropositivity (80%-100%), the rate of congenital CMV infection is 1%-5%, while in areas with relatively low CMV seropositivity (40%-70%), the rate of congenital CMV infection is 0.4%-2%.
II. Routes of CMV infection in pregnant mothers and high-risk factors 1. The route of CMV infection in pregnant mothers is commonly caused by close contact with young children, especially those attending day care centers. The risk of vertical transmission of CMV to the fetus appears to increase with gestational age in primary mothers compared with recurrent infections (32% vs. 1.4%).
2. Other factors that can influence the transmission of CMV infection during pregnancy include maternal age and the number of births (younger primiparous women are at higher risk).
3. Infants infected with primary maternal infection are more likely to be symptomatic at birth and more likely to have distant sequelae than infants infected with recurrent maternal CMV infection. However, the risk of hearing loss appears to be similar in both groups.
4. The sequelae appear to be more severe when the infection occurs earlier in pregnancy, especially in early pregnancy. However, symptomatic congenital CMV infection may result from maternal infection at any point in gestation. One study included 238 women with primary CMV infection during pregnancy and found that the incidence of symptomatic fetal infection was 14% (10 of 72 cases) when maternal infection occurred in early pregnancy, compared to 0 (54 total cases) when maternal infection occurred later in pregnancy, although the rate of viral transmission was higher in later gestation.
III. Manifestations of congenital cytomegalovirus infection 1. Intrauterine manifestations: Fetal infection in utero may be asymptomatic or may manifest as congenital CMV disease. The diagnosis and treatment of congenital CMV infection usually begins while the fetus is still in utero.
2. The following ultrasound findings are suggestive but not diagnostic of fetal CMV infection: periventricular calcification, ventricular dilatation, microcephaly, enhanced fetal gut echo (sometimes the first sign of congenital intrauterine CMV infection and a marker of disease), fetal growth restriction, hepatosplenomegaly, multiple microcephaly, cerebellar hypoplasia, presence of pseudocysts around the ventricles or adjacent to the occipital or temporal horn, strong periventricular echogenicity, enlarged cerebellar medullary pool, abnormal amniotic fluid (hypoamniotic fluid or hyperamniotic fluid), ascites and/or pleural effusion, liver calcification, fetal edema, fetal death, and placenta enlargement.
3. Clinical presentation of symptomatic newborns: Approximately 10% of congenitally CMV-infected newborns are symptomatic at birth. The clinical presentation of symptomatic neonates is similar to that of other congenitally infected neonates: petechiae (54%-76%), jaundice at birth (38%-67%), hepatosplenomegaly (39%-60%), infants younger than gestational age (39%-50%), microcephaly (36%-53%), sensorineural deafness SNHL (34% incidence at birth), lethargy and/or hypotonia (27%), sucking weakness (19%), chorioretinitis (11%-14%), seizures (4%-11%), hemolytic anemia (11%), pneumonia (8%) IV. Behavioral interventions to reduce congenital cytomegalovirus infection in pregnant women 1. adhere to good personal hygiene practices throughout pregnancy, especially the use of soap and water after contact with diapers or oral and nasal secretions Wash hands (especially after contact with daycare children) carefully for at least 15-20 seconds.
2. Avoid kissing children under 6 years old on the mouth or cheek; kiss them on the head or give them a hug.
3. Do not share food, drinks or oral utensils (such as forks, spoons, toothbrushes, soothers) with young children.
4. Clean toys, table tops, and other surfaces that children’s urine or saliva may come in contact with.