Chickenpox and pregnancy

9 out of 10 women in the UK are immune to chickenpox. This is why it is uncommon in pregnancy, affecting only 3 in every 1000 pregnant women.  

If you grew up in a tropical area, you are less likely to have had chickenpox in childhood. If you subsequently move to the UK, you have a greater risk of catching chickenpox than women who grew up in the UK. Your healthcare professional may discuss having a blood test to check whether or not you are immune. 

If you have not had chickenpox, (or you are not sure) you should avoid contact with anyone who has chickenpox or shingles while you are pregnant.  

The main symptom of chickenpox is an itchy rash that appears on any part of your body. This rash happens in stages: 

1. You may have a fever and feel unwell, and watery blisters appear on your body. 
2. The blisters begin to itch and burst. 
3. The blisters crust over and then heal. This may take up to 2 weeks. 

After coming into contact with someone who has chickenpox, the symptoms of chickenpox take between 10 days to 3 weeks to appear.  

If you are infected for the first time as an adult, it tends to be more serious. 

Shingles is related to chickenpox but the symptoms are different. After you have had chickenpox, the virus stays in your body and can become active again later and this time it causes shingles. Shingles is a patch of itchy blisters on the skin that dry out and crust over in a few days. The affected area can be very painful.

You catch chickenpox from someone who currently has it. A person is contagious from two days before the rash appears to when all the blisters have crusted over.

During this time, you can catch chickenpox by being:

• in close contact with them
• face to face with them for at least 5 minutes
• in the same room with them for at least 15 minutes.

Yes. If you have not had chickenpox, you can be vaccinated against it before you get pregnant, or after giving birth. Vaccination in adults consists of two injections 6 weeks apart.

If you have received the vaccine, and then develop a rash, you should avoid contact with pregnant women or women who are trying to get pregnant. 

No. You cannot be vaccinated in pregnancy and you should avoid getting pregnant for 1 month after the second injection.

If you find out you are not immune to chickenpox during pregnancy, your healthcare professional may discuss vaccination after the birth of your baby. You can continue to breast feed if you have the vaccine at this time. 

If you have had chickenpox, you will be immune and there is nothing to worry about. You do not need to do anything.

If you have never had chickenpox, or are not sure, see your GP as soon as possible. You can have a blood test to find out if you are immune. 8 out of 10 women in this situation will be immune without realising it.

If you develop a rash in pregnancy, you should contact your GP or midwife.

If your blood test confirms that you are not immune to chickenpox and you come into contact with it during pregnancy, you would be offered a course of antiviral tablets called aciclovir (or valciclovir). This is taken for one week, starting 7 days after you came into contact with the person with chickenpox. Aciclovir and valciclovir are not licensed in pregnancy but are considered safe.  

If you are known to have side effects from this sort of medication, you may be offered an injection of varicella zoster immune globulin (VZIG). This is a human blood product that strengthens the immune system for a short time. You can be given the injection in the 10 days after you came into contact with chickenpox and before you develop any symptoms. It does not help once you have a rash. 

Both treatments may stop you from developing chickenpox. If you do develop an infection, both treatments can make this milder and not last for as long. 

You should avoid contact with other pregnant women for up to 4 weeks after your contact with the person with chickenpox, whether or not you received treatment.  

If you start to get a rash, you should contact your GP or midwife as soon as possible. You should be wait to be seen separately from other pregnant women at your GP’s surgery or in the hospital.

What if I come into contact with chickenpox again? 

If your blood test shows that you have not become immune, you can have a second treatment. This can be another course of antiviral medication starting 7 days after contact or a second dose of VZIG if it is 3 weeks or longer since your last injection. 

Chickenpox can be serious for your health during pregnancy. Complications can occur such as chest infection (pneumonia), inflammation of the liver (hepatitis) and inflammation of the brain (encephalitis). Very rarely, women can die from complications.

You are at greater risk of complications if you catch chickenpox when you are pregnant if you:

• smoke cigarettes
• have a lung disease such as bronchitis or emphysema
• are taking steroids or have done so in the last 3 months
• are more than 20 weeks pregnant.

If any of these apply to you, you may need to be referred to hospital.

The risk of your baby catching chickenpox depends on when in your pregnancy you catch it. The highest risk is during the last 4 weeks of pregnancy.

It is safe to breastfeed if you have chickenpox during pregnancy or after the birth of your baby. If you have blisters close to your nipple you should not feed from that breast until they have crusted over. You can express milk from that breast, and ask your healthcare professional for further advice about whether you can give this to your baby.

If you catch chickenpox:

Up to 28 weeks of pregnancy

There is no evidence that you are at an increased risk of early miscarriage. Your baby is unlikely to be affected; however there is a small chance that damage could occur to the eyes, legs, arms, brain, bladder or bowel. This only happens in fewer than 1 in 100 babies. You will be referred to a fetal medicine specialist for ultrasound scans and discussion about possible tests and their risks.

Between 28 and 36 weeks of pregnancy

The virus will stay in your baby’s body but will not cause any symptoms. The virus may become active again, causing shingles in the first few years of his or her life.

After 36 weeks of pregnancy

This is the time when your baby is at greatest risk of getting chickenpox. If you have chickenpox in the 4 weeks before birth, about 1 in 4 babies will also develop chickenpox, but your antibodies will help protect your baby. 

Your baby may get severe chickenpox if: 

• your baby is born within 7 days of your chickenpox rash appearing or, 
• you get chicken pox within the first week after birth. 

This is because fewer antibodies cross to your baby. 

Your baby will be given VZIG and treated with an antiviral drug called aciclovir and monitored closely after birth. 

If you are more than 20 weeks pregnant, you can be given aciclovir to reduce fever and symptoms. This should be given within 24 hours of the chickenpox rash appearing. Aciclovir is not licensed in pregnancy but does not appear to be harmful for unborn babies and therefore may also be considered before 20 weeks. You will able to discuss the benefits and risks with your doctors.

Your GP should send you to hospital if you have chickenpox and develop any of the following:

• chest and breathing problems
• headache, drowsiness, vomiting or feeling sick
• vaginal bleeding
• a rash that is bleeding
• a severe rash.

These symptoms may be a sign that you are developing the complications of chickenpox. If this is the case, aciclovir may be given to you through a drip in your arm.

You should also be admitted to hospital if you have a condition that means your immune system does not work as well as it should (known as being immune suppressed).

If you need to be admitted to hospital, you will be nursed in a side room away from babies and pregnant women until your blisters crust over. This is normally 5 days after the onset of the rash.

The timing will depend on your own circumstances. It is best to wait until the chickenpox is over, to let you recover, so ideally at least 7 days from the onset of the rash. This will also give a chance for your immunity to pass to the baby. If you are very ill with chickenpox, particularly with any of the complications, your obstetrician will discuss whether you should have your baby early.

If your newborn baby has come into contact with chickenpox in the first 7 days of life and you are immune, your baby will be protected by your immunity and there is nothing to worry about.

If you are not immune, your baby may be given VZIG.

If you are immune to chickenpox, you do not need to worry. If you are not immune, the risk of getting chickenpox from someone with shingles on a covered part of the body is very small. If the shingles is widespread or exposed (such as the face or eye), there is a risk of chickenpox infection to you when the blisters are active and until they are crusted over. See your doctor for advice about treatment.

If you get shingles while you are pregnant, it is usually mild and there is no risk for you or your baby. However, you can spread the infection before the blisters crust over. So, if you have shingles, you should avoid contact with other pregnant women , as well as babies less than 1 month old.