Chickenpox during pregnancy

Chickenpox (also called varicella) is a common infection in children. It can be harmful to your unborn baby or newborn if you get it during pregnancy. 

You probably don’t need to worry about chickenpox if you’ve had it before or if you’ve had the chickenpox vaccine. Both of these can help make you immune to chickenpox. Immune means being protected from an infection. If you're immune to an infection, it means you can't get it. About 9 out of 10 pregnant women (90 percent) are immune to chickenpox. A vaccine is a medicine you get that helps protect against certain diseases. 

Many women don’t know if they’re immune to chickenpox. If you’re not sure, talk to your health care provider about chickenpox during your first prenatal visit.

What is chickenpox?

Chickenpox is caused by a virus. People usually get it during childhood. Its symptoms include an itchy rash, blisters and fever. These symptoms show up about 2 weeks after you get the chickenpox virus. The infection usually isn’t dangerous in children. But 1 to 2 out of 10 pregnant women (about 10 to 20 percent) who get chickenpox get a dangerous form of pneumonia (a kind of lung infection).

You can get chickenpox by being in contact with someone else’s chickenpox rash. It’s also spread through the air when someone with chickenpox coughs or sneezes. An infected person can spread chickenpox starting 1 to 2 days before the rash appears and until the rash stops spreading and is covered by dry scabs. This usually is about 5 days after the rash starts.

How do you know if you have chickenpox?

Tell your provider right away if you come into contact with someone who has chickenpox.

Your provider can tell you if you have chickenpox by doing a physical exam. Sometimes, your provider takes a swab of the rash and sends it to a laboratory for testing to be sure it’s chickenpox.

Can chickenpox hurt your baby during pregnancy?

Yes, but most likely your baby will be born healthy. But some babies may get congenital varicella syndrome. This is a group of birth defects that can include:

  • Scars
  • Problems with muscles and bones
  • Arms or legs that are paralyzed or not formed correctly
  • Blindness
  • Seizures
  • Learning problems
  • Microcephaly. This is a birth defect in which a baby’s head is smaller than expected, compared to babies of the same sex and age.

Only about 1 or 2 out of 100 babies (1 to 2 percent) whose mothers had chickenpox during the first 20 weeks of pregnancy get congenital varicella syndrome. Your provider can do an ultrasound to check for some birth defects caused by chickenpox.

Birth defects are very rare when you get infected with chickenpox after 20 weeks of pregnancy. But your baby could have problems with his central nervous system (brain and spinal cord) if you get infected in the third trimester of pregnancy.

Infection after 20 weeks of pregnancy also may cause shingles in your baby during the first 1 to 2 years of life. Shingles (also called herpes zoster) is an infection caused by the same virus that causes chickenpox. A person with shingles has painful clusters of blisters that usually appear on a small area of the body. Shingles doesn’t seem to cause birth defects or infections in your baby.

Can chickenpox hurt your newborn baby?

It depends on when the infection happens. If you get a chickenpox rash about 1 to 3 weeks before giving birth, there’s some chance that you can pass the infection to your baby. But if that happens, the infection is usually mild.

But if you get a chickenpox rash the week before you give birth or within a couple days after giving birth, there is up to a 3 in 10 chance (30 percent) that your baby will get a serious, even deadly, form of the infection.

How is chickenpox treated during pregnancy?

If you get chickenpox while you’re pregnant, your provider gives you an antiviral called acyclovir to help with the symptoms. An antiviral is a medicine that kills infections caused by viruses. Studies have shown that this medicine is safe during pregnancy. If you start to get any signs of pneumonia, you need to be hospitalized and treated with a higher amount of antivirals through an IV (when medicine is given through a needle into a vein.).

How is chickenpox treated in your newborn baby?

If your newborn has the serious form of the infection, your provider treats your baby right after birth with medicine that has chickenpox antibodies. Antibodies are cells in the body that fight off infection. The medicine can help prevent chickenpox in your baby or make it less dangerous.

If your baby still gets chickenpox after getting treated, she can be treated with an antiviral like acyclovir.

How can you avoid chickenpox during pregnancy if you aren't immune?

First, get a blood test to find out if you’re immune to chickenpox. Get tested if you’re pregnant or planning to get pregnant. If you’re not immune, you can get a vaccine. It’s best to wait 1 month after the vaccine before getting pregnant.

If you’re already pregnant, don’t get the vaccine until after you give birth. In the meantime, avoid contact with anyone who has chickenpox or shingles.

If you’re not immune to chickenpox and you come into contact with someone who has it, tell your provider right away. Your provider can treat you with medicine that has chickenpox antibodies. It’s important to get treatment within 4 days after you’ve come into contact with chickenpox to help prevent the infection or make it less serious.

Also, tell your provider if you come in contact with a person who has shingles. Your provider can treat you with the antiviral acyclovir.

Can you get chickenpox from a child who just had a vaccine?

Not usually, but it can happen if a child gets sores after having the vaccine. Sores can appear around the area where the child got the vaccine. Make sure your children are vaccinated for chickenpox at ages 12 to 15 months and at 4 to 6 years. Your chances of getting chickenpox from a child who recently had a vaccine are much lower than the chances of getting it from a child who doesn’t have the vaccine.

What are the chances of getting chickenpox during pregnancy?

About 1 out of 1,000 pregnant women in the United States gets chickenpox. Most children get chickenpox vaccines, so the chances of getting it are becoming even lower.

Nine out of 10 pregnant women (90 percent) who aren’t immune to chickenpox get the infection when someone else in their home has it.

See also:
Vaccinations and pregnancy

Last reviewed: December, 2014