There are two main routes by which intrauterine and intrapartum infections are transmitted. Transplacental infection results from maternal viremia and may take place any time during pregnancy. CMV and rubella are the most commonly transplacentally transmitted viruses, but HSV and VZV can also reach the fetus via this route. Infection during delivery can also occur and is the major route of transmission for hepatitis B and C and HIV. Table 6 summarizes the route of transmission of selected congenital and neonatal virus infections.
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