I. The most common cause of congenital viral infection in US (0.2-2.2% of live births)

II. Epidemiology and risk factors

  1. Probably transmitted by a wide variety of routes
  2. Health care workers are probably at highest risk for infection.
  3. Fetus can be infected with both primary and recurrent maternal infections, though much less common with recurrent infections. Positive viral cultures from urine, cervix, etc. correlates poorly with risk of congenital infection

III. Mom is usually asymptomatic, although can occasionally get a "mono-like" syndrome.

IV. Congenital infection

  1. Occurs in about 40% of maternal primary infections.
  2. Risk of symptomatic infection of fetus is greatest with infection early in pregnancy, though precise risk is unknown.
  3. 90% asymptomatic at birth, though can show damage, including symmetric IUGR, hepatosplenomegaly, chorioretinitis, micropthalmia, cerebral calcifications, hydrocephaly, & microcephaly
  4. Subsequently may show deafness & mental retardation.
  5. Diagnosis is usually by prenatal ultrasound; can also culture from amniotic fluid
  6. Treatment and prevention of congenital infection
    1. IV hyperimmune globulin
      1. In a non-randomized study in 45 pregnant women with primary CMV infection and CMV detected in amniotic fluid, of whom 31 received IV hyperimmune globulin and 14 did not, treatment was associated with sig. lower incidence of clinical congenital CMV disease (3% vs. 50%).  The same paper also reported outcomes in a cohort of 84 pregnant women with primary CMV infection who had not undergone amniocentesis (the "prevention" arm of the study) of whom 37 received IV hyperimmune globulin; incidence of clinical congenital CMV disease was sig. lower in IG recipients (16% vs. 40%) (NEJM 353:1350, 2005--JW)
  7. May also be transmitted from mother to infant through breastfeeding in the neonatal period, though disease was generally mild in one case series (J. Peds. 154:842, 2009-JW)