In every pregnancy, a woman starts out with a 3-5% chance of having a baby with a birth defect. This is called her background risk. This sheet talks about whether exposure to the varicella (chickenpox) vaccine may increase the risk for birth defects over that background risk. This information should not take the place of medical care and advice from your health care provider.

What is varicella (chicken pox)?

Varicella, commonly called chicken pox, is a viral infection that usually happens in childhood. The most common symptom is a rash, which first appears as small, reddish spots or pimples. These spots will blister and then scab over. New spots appear for up to 3-5 days. Often a fever and body aches occur before the rash appears. Pneumonia also occurs in 10-15% of teenagers and adults who have chicken pox.

Chicken pox is very contagious, meaning it can spread easily from person to person. A person who has chicken pox is contagious 1-2 days before they break out in their rash and continue to be contagious until all of their spots are scabbed over. If you have never had chicken pox before, there is a 90% chance that you will catch it if someone in your house has it. The best way to prevent chicken pox infection is through vaccination. For more information, see the MotherToBaby fact sheet on Chicken Pox at:

I have never had chicken pox and just received the varicella vaccine. How long must I wait before becoming pregnant?

The vaccine maker recommends waiting three months before trying to conceive. This is based on the waiting period for other vaccines that use a live virus. Some people develop a rash from the varicella vaccine. If a rash is present, it is possible to infect another person.

The American Academy of Pediatrics and the Advisory Committee on Immunization Practices of the CDC recommends that a woman wait one month after receiving the varicella vaccine before becoming pregnant. There are reports of normal babies born to women who conceived (became pregnant) one month or sooner after getting the chicken pox vaccine.

I am pregnant. Can I be vaccinated against chicken pox with the varicella vaccine?

The American Academy of Pediatrics and the Advisory Committee on Immunization Practices of the CDC does not recommend pregnant women get live virus vaccines due to theoretical concerns.

I am 6 weeks pregnant. I received the varicella vaccine last week. Will this hurt my baby?

The company who makes the vaccine compiled a registry of pregnant women who received the vaccine. As of closing the registry in 2012, they had pregnancy outcomes on 928 women who received the vaccine. There was no increase in birth defects over the general population chance. This is reassuring information.

I am pregnant and have never had chicken pox. Is it okay for my child to get the chicken pox vaccine?

Yes, the American Academy of Pediatrics states that pregnancy in a mother or other household member is not felt to be a reason to avoid giving a child the vaccine.

The vaccine uses a live but weakened varicella (chicken pox) virus. Some people get a rash after they get the vaccine. Only when this rash is present is there a chance to infect someone else. Children with weakened immune systems (e.g. from cancer therapy) can pass the virus on to others, who can then develop a mild case of chicken pox.

To date, no cases of chicken pox have occurred after exposure to healthy children who have received the varicella vaccine.

Can I get the varicella vaccine if I am breastfeeding?

Yes. The chicken pox virus has not been found in breast milk of women receiving the vaccine. Be sure to talk to your health care provider about all your choices for breastfeeding. Be sure to discuss all of your breast feeding questions with your healthcare provider.

I am immune to chicken pox, but what if the father of the baby is infected?

There are no studies looking at possible risks to a pregnancy when the father has chicken pox. Infection of the father is unlikely to increase the risk to a pregnancy. In general, exposures that fathers have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures and Pregnancy at

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