Perinatally acquired infections and screening.

For hepatitis B, universal screening of pregnant women for HBsAg along with the combined use of hepatitis B vaccine and HBIG in infants of infected mothers appears to be the best way to detect and prevent vertically transmitted infection. Cytomegalovirus is the most common congenital viral infection, but the lack of a good screening test precludes its accurate and rapid diagnosis. For HPV-B19, larger and more controlled studies are needed to confirm the safety and effectiveness of fetal blood transfusions in the management of hydrops fetalis caused by this infection. Finally, the fact that most mothers of HSV- and toxoplasma-infected neonates have no history of infection, and are asymptomatic at the time of delivery, underscores the need for a high index of clinical suspicion in sick neonates.