Congenital and Perinatal Cytomegalovirus Infection (CMV)

Congenital CMV infection, which occurs in 0.2 to 1% of live births worldwide, may result from transplacental acquisition of either a primary or recurrent maternal infection. Clinically apparent disease in the neonate is much more likely to occur after a primary maternal exposure, particularly in the first half of pregnancy. In some higher socioeconomic groups in the US, 50% of young women lack antibody to CMV, making them susceptible to primary infection.

Perinatal CMV infection is acquired by exposure to infected cervical secretions, breast milk, or blood products. Maternal antibody is thought to be protective, and most exposed term infants are asymptomatic or not infected. In contrast, preterm infants Preterm Infants An infant born before 37 weeks gestation is considered preterm. Prematurity is defined by the gestational age at which infants are born. Previously, any infant weighing < 2.5 kg was termed... read more (who lack antibody to CMV) can develop serious infection or can die, particularly when transfused with CMV-positive blood. Efforts should be made to transfuse these infants with only CMV-negative blood or components or to use blood that has been filtered to remove leukocytes, which carry CMV. Such leukoreduced blood is considered by many experts to be CMV safe.

Many women who become infected with CMV during pregnancy are asymptomatic, but some develop a mononucleosis Infectious Mononucleosis Infectious mononucleosis is caused by Epstein-Barr virus (EBV, human herpesvirus type 4) and is characterized by fatigue, fever, pharyngitis, and lymphadenopathy. Fatigue may persist weeks or... read more -like illness.

About 10% of infants with congenital CMV infection are symptomatic at birth. Manifestations include the following:

Infants who acquire CMV during or after birth, especially if they are premature, may develop a sepsis-like syndrome, pneumonia, hepatosplenomegaly, hepatitis (which can lead to liver failure), thrombocytopenia, and atypical lymphocytosis. However, if transmission is via breast milk, the risk of severe symptomatic disease and long-term sequelae is low.

Symptomatic congenital CMV infection must be distinguished from other congenital infections, including toxoplasmosis Congenital Toxoplasmosis Congenital toxoplasmosis is caused by transplacental acquisition of Toxoplasma gondii. Manifestations, if present, are prematurity, intrauterine growth restriction, jaundice, hepatosplenomegaly... read more , rubella Congenital Rubella Congenital rubella is a viral infection acquired from the mother during pregnancy. Signs are multiple congenital anomalies that can result in fetal death. Diagnosis is by serology and viral... read more , lymphocytic choriomeningitis virus (LCMV), and syphilis Congenital Syphilis Congenital syphilis is a multisystem infection caused by Treponema pallidum and transmitted to the fetus via the placenta. Early signs are characteristic skin lesions, lymphadenopathy... read more .

In neonates, viral detection using culture or PCR of urine, saliva, or a tissue sample is the primary diagnostic tool; maternal diagnosis can also be made by serologic testing or PCR ( see Diagnosis Diagnosis Cytomegalovirus (CMV, human herpesvirus type 5) can cause infections that have a wide range of severity. A syndrome of infectious mononucleosis that lacks severe pharyngitis is common. Severe... read more ). Culture specimens should be refrigerated until inoculation of fibroblast cells. Congenital CMV is diagnosed if the virus is identified in urine, saliva, or other body fluids obtained within the first 2 to 3 weeks of life; urine and saliva have the highest sensitivity. After 3 weeks, viral detection may indicate perinatal or congenital infection. Infants may shed CMV for several years after either type of infection.

A complete blood count (CBC) with differential and liver tests may be helpful but are not specific. Cranial ultrasonography or CT and an ophthalmologic evaluation should also be done. Periventricular calcifications are commonly found on CT.

Hearing tests should be routinely done at birth in all infected neonates, and continued close monitoring is required because hearing loss may develop after the neonatal period and be progressive.

Symptomatic neonates have a mortality rate of up to 30%, and 40 to 90% of survivors have some neurologic impairment, including

Among asymptomatic neonates, 5 to 15% eventually develop neurologic sequelae; hearing loss is the most common.

Symptomatic neonates are given antiviral drugs. Oral valganciclovir 16 mg/kg 2 times a day for 6 months decreases viral shedding in neonates with congenital CMV and modestly improves hearing and developmental outcomes at 12 and 24 months of age (1 Treatment reference Cytomegalovirus infection may be acquired prenatally or perinatally and is the most common congenital viral infection. Signs at birth, if present, are intrauterine growth restriction, prematurity... read more ). In utero treatment of affected fetuses with acyclovir or valacyclovir may also improve neonatal outcomes, but large studies are lacking.

The main toxicity of treatment is neutropenia Neutropenia Neutropenia is a reduction in the blood neutrophil count. If it is severe, the risk and severity of bacterial and fungal infections increase. Focal symptoms of infection may be muted, but fever... read more .

Nonimmune pregnant women should attempt to limit exposure to the virus. For instance, because CMV infection is common among children attending day care centers, pregnant women should always wash their hands thoroughly after exposure to urine and oral or respiratory secretions from children.

Transfusion-associated perinatal CMV disease can be avoided by giving preterm neonates blood products from CMV-seronegative donors or leukoreduced products.

A vaccine to prevent congenital CMV is under development. CMV hyperimmune globulin given to pregnant women with primary CMV infection did not show a reduction in congenital infection in a randomized, controlled trial (1 Prevention references Cytomegalovirus infection may be acquired prenatally or perinatally and is the most common congenital viral infection. Signs at birth, if present, are intrauterine growth restriction, prematurity... read more ). Maternal antiviral therapy with acyclovir or valacyclovir to prevent fetal transmission is being investigated (2 Prevention references Cytomegalovirus infection may be acquired prenatally or perinatally and is the most common congenital viral infection. Signs at birth, if present, are intrauterine growth restriction, prematurity... read more ).