In the UK, it’s estimated that nine out of ten pregnant women (90%) in the UK are already immune to chickenpox (varicella). Once you have had chickenpox, it’s extremely rare to catch it a second time, so there’s therefore no need to worry about catching chickenpox in pregnancy. If you’re sure you’ve had chickenpox, you don’t need to do anything as your body will have developed antibodies to the virus, making you immune to further infection.
What if I come into contact with chickenpox when I am pregnant?
Because most women are already immune to chicken pox, it’s rare to catch it during pregnancy. Only about three in every 1,000 (0.3%) of pregnant women in the UK will develop chickenpox and even fewer babies are affected in the uterus. If you do catch chickenpox during pregnancy, it can cause complications both for the pregnant woman and the unborn baby. However, most pregnant women who get chickenpox in pregnancy recover, with no adverse effects to themselves or the baby.
Chickenpox is highly infectious and if you have come into contact with someone with chickenpox and you’ve never had chickenpox, or you’re not sure, see your GP as soon as possible. You can have a blood test to find out if you are immune, which may take between 24 hours and 48 hours to get the results.
Alternatively, if you’ve had your booking appointment and had a blood sample taken, the hospital may have saved some serum. The hospital can then arrange to run the chickenpox test from the serum and you will know very quickly if you are immune.
What if I’ve come in contact with chickenpox during pregnancy and I’m not immune?
If a blood test confirms you are not immune to chickenpox and you come into contact with it, or shingles, during pregnancy, you may be offered an injection of varicella zoster immune globulin (VZIG). This is a human blood product which strengthens the immune system for a short time. VZIG does not necessarily prevent chickenpox developing but can make the infection milder and not last for as long. The injection should ideally be given within 72 hours of exposure, but can be given up to 10 days after you first came into contact with chickenpox or shingles, and before any of your symptoms appear. VZIG does not work once you have blisters. If you go on to develop a rash, tell your doctor as soon as possible.
If you come into contact with chickenpox again and it is 3 weeks or longer since your last injection, you can be given a second dose of VZIG.
How do you catch chickenpox?
Chickenpox is an airborn virus and spreads in the air from person to person. It’s highly contagious, and if you haven’t had chickenpox before, you have a high chance of catching it if you’re in close contact with someone who has it. Face-to-face contact for at least 5 minutes and being in the same room with an infected person for more than 15 minutes both increase the chances of you getting chickenpox.
What about shingles and pregnancy?
You can also catch chickenpox from someone who has shingles, which is caused by the same virus as chickenpox. So you should avoid contact with people with shingles if you haven’t had chickenpox before. If you have shingles during pregnancy it won’t affect your baby.
What are the symptoms of chickenpox?
The symptoms of chickenpox take between 10 days to 3 weeks to appear. This is the incubation time – the time from when you catch it to when the symptoms start to show.
The first signs are usually a fever, headache, stomach ache, loss of appetite and feeling generally unwell. This is followed by the appearance of itchy, watery blisters, which can appear anywhere over the body and can vary in number and severity. After a few days, the blisters burst, crust over and then heal. This may take up to 2 weeks.
Are there any treatments if I develop chickenpox during pregnancy?
It’s safe to take paracetamol and this can help with the pain and fever linked with chickenpox. Topical calamine lotion is also safe to use to reduce the itchiness of your blisters. Try to drink plenty of fluids and get plenty of rest.
You may be offered an anti-viral drug called aciclovir within 24 hours of the chickenpox rash appearing. After this time, it’s not effective. This won’t cure the virus but can help to reduce your fever and other symptoms. Aciclovir is only recommended if you are more than 20 weeks pregnant due to the risk of the drug affecting your baby.
What are the risks to my baby during pregnancy if I catch chicken pox?
The risk to the baby depends on what stage in pregnancy you catch chickenpox. Catching chickenpox in your first trimester does not increase your risk of miscarriage, but there could be other potential problems if the virus affects your baby during pregnancy or as a newborn.
If you get chickenpox during pregnancy, there’s a small chance that your baby may develop fetal varicella syndrome (FVS). This may mean your baby is born with serious abnormalities such as scars, eye problems and shortened limbs. Your baby may also have neurological problems, which cause bladder and bowel problems, and as your baby gets older, they may take a longer time to reach their developmental milestones.
The risk of chickenpox affecting your baby depends on when in your pregnancy you catch it:
- Before 13 weeks, the risk is very small, with only 0.5-1% of babies suffering any side effects of FVS.
- Between 13 weeks and 28 weeks the risk increases very slightly to 2% of babies being affected by FVS.
- Between 28 weeks and 36 weeks your baby is very unlikely to be affected, but the virus may become active again in the first few years of the child’s life, causing shingles.
- After 36 weeks your baby is more likely to become infected, a one in two chance, and could be born with chickenpox.
- If the baby is born within seven days of your chickenpox rash appearing, your baby may go on to get severe chickenpox.
After 36 weeks, a doctor may consider giving your baby an injection of VZIG. This won’t necessarily stop them from catching chickenpox but a VZIG injection may reduce the severity of the symptoms. Anti-viral treatment with aciclovir is another option for newborns who have chickenpox.
It is safe to breastfeed if you have chickenpox or have had it during pregnancy.
How can I find out if my baby has been affected?
If you have had chickenpox during early pregancy, you are likely to be offered a detailed ultrasound scan between 16 weeks and 20 weeks of pregnancy,which will check your baby’s organs. If you develop chickenpox later in pregnancy, the scan will need to be carried out five weeks after your symptoms have cleared.
Your doctor or sonogropher might also be able to see on the scan whether your baby’s brain and limbs are developing as they should. However, ultrasound can’t detect every type of birth defect, so a scan isn’t a guarantee that your baby has been unaffected by the virus.
After birth, the baby will have an eye examination and may be offered blood tests.
What about my health if I catch chickenpox in pregnancy?
It’s very likely that you’ll recover fully and you and your baby will be fine after you’ve had chickenpox. However, chickenpox can cause serious complications for your health during pregnancy, such as a sever chest infection (pneumonia), inflammation of the liver (hepatitis) and inflammation of the brain (encephalitis). Very rarely, women can die from complications.
The following symptoms can be a sign you are developing the above complications of chickenpox. You should see your doctor immediately if you develop any of the following:
- chest and breathing problems
- vomiting or feeling sick
- vaginal bleeding
- a rash that is bleeding
- a severe rash
- drowsiness or lethargy
If you catch chickenpox in pregnancy or when you are trying to become pregnant, you should avoid contact with other pregnant mothers and new babies until all your blisters have crusted over.
By Amber – babyworld midwife
Feb 2012
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