Pregnant women who have chickenpox are at risk of complications. The type of complications depend on when the infection developed during pregnancy.

• Pregnant women who have chickenpox during the first half of pregnancy may go into labor early (premature labor) or have a miscarriage.
• Pregnant women who have chickenpox in the last part of pregnancy are more likely to develop varicella pneumonia. Even a healthy pregnant woman is at risk of dying if she develops varicella pneumonia.
• Up to 2 out of 100 fetuses whose mothers have chickenpox during the first 20 weeks of pregnancy will also get chickenpox.¹ This is called congenital varicella and can cause:
  • Birth defects. Birth defects can include one limb (usually a leg) smaller than the other, scars on the limbs, or eye problems such as cloudy lenses.
  • Low birth weight (weigh less than expected at birth).
  • Seizures. The baby can have seizures after birth.
  • Mental retardation.
  • Shingles. Fetuses who have chickenpox will not have chickenpox again. But they can still have shingles, even as babies or young children.
  • Death. Up to 7 out of 100 of the fetuses who get congenital varicella die.²
• Babies born within a few days of their mothers' chickenpox infection have a risk of severe chickenpox infection. These babies are at greater risk of complications from chickenpox.