Chicken Pox and Pregnancy

When you become pregnant you want to do everything you can to stay healthy. Unfortunately, it is sometimes impossible to protect yourself from every illness out there. Chicken pox is a highly contagious viral infection that can be very serious. Fortunately, there are ways to protect you and your baby if you are threatened by chicken pox.

What exactly is chicken pox?

Chicken pox is a viral infection also called varicella. It is accompanied by a rash, which appears as small reddish spots or pimples. A fever and body aches usually occur before the rash appears. In most cases chicken pox is contracted during childhood, although there are some instances when an adult is not immune and contracts chicken pox. About 95% of women in their childbearing years are immune to chicken pox.

Who is most at risk for getting chicken pox during pregnancy?

  • If you have been infected with chicken pox once before, then you are most likely immune to getting chicken pox again.
  • If you have NOT been infected with chicken pox and are pregnant, you may be at risk of contracting the virus. You will want to avoid contact with anyone who has chicken pox.
  • If you are not sure if you have ever been infected with chicken pox, your doctor can give you a blood test to determine if you have the chicken pox antibodies. If the test shows that you have antibodies, then you are immune to chicken pox.

How will my baby be affected if I have chicken pox?

How your baby will be affected depends on where you are at in your pregnancy. According to the Organization for Teratology Information Service (OTIS):

  • If chicken pox occurs within the first trimester, the risk of birth defects is 0.5-1 percent
  • If chicken pox occurs within the 13th and 20th week, the risk of birth defects is 2 percent
  • If chicken pox occurs within 5 days or less of delivery or 1-2 days after delivery, there is a 20-25% chance that your baby will develop chicken pox, known as congenital varicella.
  • If chicken pox occurs within 6-12 days before delivery, there is a chance that the baby can still get chicken pox. In this case your baby may receive some of your newly made chicken pox antibodies, which will cause the congenital varicella to be mild.

Possible birth defects may be scars, eye problems, poor growth, small head size, delayed development, and/or mental retardation.

What can I do to protect my baby from chicken pox?

  • If you have had chicken pox before, then there is nothing you need to do to protect your baby during pregnancy. Your body should have antibodies that protect you from contracting chicken pox; therefore, your baby will be protected.
  • If you have not had chicken pox before, you may receive the shot of zoster immune globulin (ZIG) if you are pregnant and come in contact with someone who has chicken pox. ZIG must be given with 4 days of first exposure. This is only given if you do not already have the antibodies against chicken pox.
  • You can get a chicken pox vaccine if you do not have the chicken pox antibodies and you are not pregnant. You must wait 3 months before trying to conceive.

Can someone get chicken pox twice?

It is rare that a person will contract chicken pox twice, but those with immune problems are at an elevated risk of a second infection. There are also those cases when people think they had chicken pox when they were younger, when in fact it was just a rash or something else.

Last Updated: 12/2006

Compiled using information from the following sources:

Organization of Teratology Information Services, http://otispregnancy.org/pdf/chickenpox.pdf

Williams Obstetrics Twenty-Second Ed. Cunningham, F. Gary, et al, Ch. 46.