Chickenpox is rare during pregnancy (1 to 7 per 10,000). The infection can be severe for the mother and indirectly may affect the fetus. Before 20 weeks of amenorrhea, the varicella-zoster virus may be responsible for a rare embryofetopathy (incidence rate: 0.4 to 2%). After the 20th week of amenorrhea, fetal infection is not symptomatic, but it may lead to neonatal or infantile herpes zoster infection. During the perinatal period, a primary maternal infection may be responsible for severe neonatal varicella if delivery occurs prior to maternal antibody production. Practical guidelines are proposed according to the date of infection during pregnancy and prenatal diagnosis using amniocentesis and/or cordocentesis is discussed.