Risk of fetal varicella syndrome if maternal chickenpox:
- risk of the syndrome in children exposed to chickenpox in utero is around 0.5% if maternal chickenpox develops at 2-12 weeks of pregnancy
- 1.4% if it develops at 12-28 weeks
- 0% if it develops from 28 weeks onwards
- overall risk in the first 20 weeks of pregnancy is 0.91%
- Drug and Therapeutics Bulletin 2005; 43(12): 94-95.