Varicella zoster virus infection during pregnancy: the limits of prenatal diagnosis.

In a mother with clinical evidence of chicken-pox at 12.5 weeks, fetal herpes varicella zoster infection was revealed by transient fetal ascites with liver calcifications at 27 weeks routine ultrasound. At 27 and 35 weeks fetal blood sampling and amniocentesis failed to demonstrate fetal viral infection. However, the diagnosis was confirmed postnatally based on thoracic herpes zoster at 8 months in an otherwise healthy infant. Polymerase chain reaction (PCR) on stored amniotic cells performed retrospectively was positive for varicella zoster virus (HVZV). This observation suggests that (1) in contrast to PCR, conventional fetal biology lacks sensitivity for prenatal diagnosis of HVZV infection, (2) the association of fetal sonographic abnormalities and positive amniotic PCR can be associated with a favorable pediatric outcome. Therefore, prenatal diagnosis of HVZV infection should be considered with the greatest caution.