Chickenpox in pregnancy: revisited.

Varicella infection during the first and second trimester of pregnancy may increase the risk for congenital varicella syndrome 0.5-1.5% above the baseline risk for major malformation. Third trimester infection may lead to maternal pneumonia which can be life threatening if not treated appropriately. Varicella-zoster immune globulin (VZIG) should be administered as soon as possible preferably within 96 h from exposure to prevent maternal infection or subsequent complications. Later than 96 h, the effectiveness of VZIG has not been evaluated. Neonatal varicella is more severe if maternal rash appears 5 days prior to or 2 days after delivery. The newborn should be given VZIG immediately. Intravenous acyclovir is recommended for maternal pneumonia and severely affected neonate. No controlled study has yet evaluated the effectiveness of acyclovir or valacyclovir for postexposure prophylaxis to pregnant women or neonates. Unlike primary varicella infection in pregnancy, herpes zoster has not been documented to cause complications unless in the disseminated form. The advent of advanced imaging techniques and molecular biotechniques has improved prenatal diagnosis. With increase use of vaccination, the incidence of chickenpox in pregnancy is expected to decline in the future.