Congenital varicella syndrome is a rare complication of infection with maternal varicella before 20 weeks of pregnancy. Prospective studies in Europe and North America have shown that the incidence of congenital varicella syndrome in maternal varicella contracted in the first 20 weeks of pregnancy is about 1%–2%.1,2 Based on this estimated risk (1%), on an estimated risk of varicella infection during pregnancy of two maternal infections per 1000 pregnancies and on the annual birth rate, the number of expected cases of congenital varicella syndrome per year is approximately 41 in the United States, 4 in Canada, 7 in the United Kingdom and 7 in Germany.3 This congenital infection may be associated with severe anomalies, such as limb hypoplasia, neurologic defects, eye diseases and skin lesions. Nearly 30% of infants born with signs of congenital varicella syndrome die during the first few months of life.4
Numerous reviews have underlined the possibility of preventing congenital varicella syndrome using varicella vaccination or passive immunization. Nevertheless, the syndrome has to be considered a worldwide unsolved medical problem to date. About 150 case reports of congenital varicella syndrome have been published in the English and German literatures, with three listed in the PubMed database of the National Library of Medicine in 2010. These data are a reminder for all health professionals who counsel women who have been in contact with chicken-pox early in pregnancy to keep in mind the potential risks and permanent consequences of possible fetal infection with varicella-zoster virus.