Is a congenital infection of chickenpox dangerous to a newborn baby?

Yes. Infection in the first 20 wks can result in fetal death or damage.During the 2nd 20 wks an inapparent varicella may occur with unexplained zoster in infancy. It can be fatal if mom develops it from 5 days before to 2 days after delivery.Close consultation with your physician can reduce your chance of a bad outcome by early identification and treatment of treatable issues.See aap/redbook/varicella.