What are the risks of chickenpox during pregnancy?

Chickenpox during pregnancy can cause complications, both for the pregnant woman and the unborn baby. However, the actual risk of any complications occurring is low.

It’s rare to get chickenpox when you’re pregnant. In the UK, it’s estimated that just 3 in every 1,000 women (0.3%) catch chickenpox during pregnancy.

Most pregnant women who get chickenpox recover, with no adverse effects on the baby.

When to get medical advice

Seek advice from your GP or midwife immediately if you’re pregnant and:

  • you think you may have chickenpox
  • either you've never had chickenpox or you’re not sure, and you've been near someone that has it (even if you have no rash or other symptoms)
  • you get chicken pox within seven days of giving birth

Complications for pregnant women

You have a higher risk of complications from chickenpox if you’re pregnant and:

  • smoke
  • have a lung condition, such as bronchitis or emphysema
  • are taking or have taken steroids during the previous three months
  • are more than 20 weeks pregnant

Up to 1 in 10 pregnant women with chickenpox can develop pneumonia (inflammation of the lungs). Other rare complications include inflammation of other parts of the body, such as the:

  • brain (encephalitis)
  • liver (hepatitis)

Very rarely, complications that arise from catching chickenpox during pregnancy can be fatal.

Complications for the unborn baby

Complications that can affect the unborn baby vary, depending on how many weeks pregnant you are when you catch chickenpox.

There’s no evidence that catching chickenpox up to 28 weeks into pregnancy increases your risk of suffering a miscarriage. However, there’s a small risk the baby can develop foetal varicella syndrome (FVS). FVS can damage the baby’s skin, eyes, legs, arms, brain, bladder or bowel.

If you catch chickenpox between weeks 28 and 36 of pregnancy, the virus stays in the baby's body but doesn't cause any symptoms. However, it may become active again in the first few years of the baby’s life, causing shingles.

If you catch chickenpox after 36 weeks, the baby may be infected and could be born with chickenpox.

Complications for the newborn baby

The baby may develop severe chickenpox and will need treatment if you catch it:

  • around the time of birth and the baby is born within seven days of your rash developing
  • up to seven days after giving birth

For more information about treatment, see How is chickenpox treated during pregnancy?

Read more information about the complications of chickenpox during pregnancy and pregnancy in general.

Further information:

Page last reviewed: 28/02/2014

Next review due: 28/02/2016