Abstract

In September 2005, we published an article on Chickenpox, pregnancy and the newborn.1 One of the issues it considered was fetal varicella syndrome, an uncommon but potentially fatal consequence of in-utero chickenpox infection. We reported evidence suggesting that contracting maternal chickenpox within the first 28 weeks of pregnancy can lead to fetal varicella syndrome. This suggestion was questioned after publication since it was at odds with national guidance in the UK2–5 and elsewhere,6–9 which has indicated that fetal varicella syndrome occurs only where maternal chickenpox develops before 20 weeks of pregnancy. Here we discuss in more detail the basis for our conclusion and its implications.