Chickenpox or Shingles (Varicella Virus)--First-time exposure to this virus during pregnancy may cause miscarriage, multiple birth defects, and severe disease in newborns. Chickenpox can be a serious illness in adults. Most people (90% to 95% of adults) were exposed to chickenpox as children and are immune. For women who do not know if they had chickenpox as a child, a blood test can verify if they are immune. If they are not immune, a chickenpox vaccine is now available. Vaccination against chickenpox before you get pregnant may reduce the risk of passing the virus to your fetus should you.
