Ascending in utero herpes simplex virus infection in an initially healthy-appearing premature infant.

The usual route of acquisition for intrauterine herpes simplex virus (HSV) infection is transplacental. We evaluated a premature infant with in utero acquisition of HSV resulting from ascending infection. Histopathologic evidence of chronic chorioamnionitis and positive staining with immunohistochemistry for HSV in the placenta and umbilical cord established the diagnosis. The clinical presentation was also of interest in that the infant was initially healthy appearing.