Chickenpox in pregnancy
Chicken pox is an infectious disease caused by the varicella zoster virus. Most people in the UK have chickenpox as a child. If you did, you’re probably immune to the infection. If you were born and lived outside the UK as a child, you may be less likely to have had it. If you’re not sure whether you’re immune or not, you can ask your doctor for a blood test.
If you’re not immune, it may be a good idea to try and avoid people with chickenpox whilst pregnant if possible. If you do come into contact with chickenpox during your pregnancy then you or your baby could be at risk. The risk depends on at which stage of your pregnancy you are or if you’ve just given birth. You can have treatment that will help but you’ll need to see your doctor as soon as you know that you’ve been in contact with chickenpox, or if you develop a chickenpox rash.
If you’re concerned about your risk from chickenpox you should consult your midwife or doctor for further advice.
How do I know if I have chickenpox?
The first thing you may notice is that you have a fever (raised temperature). You may have a runny nose, a cough or feel tired. Sometimes the first thing you may notice is a rash which usually comes a day or so after the runny nose and fever. The rash quickly turns into fluid-filled blister-type spots. They often start on the head and neck and then spread to the rest of the body. The rash can be very itchy.
How easy is it to catch chickenpox?
Chickenpox is very easy to catch and can be spread by coughing or sneezing, as the virus is in the fluid in the mouth and throat of an infected person. The liquid in the spots is also infectious until the scabs appear. Just 15 minutes in a room with someone who has chickenpox or five minutes of face-to-face conversation may be enough to catch it. (These timings are used to assess your risk of having contracted the illness.)
Someone with chickenpox is infectious from two days before the spots appear until the last of the spots have scabbed over and dried up. This may take up to five days.
It takes between one and three weeks for someone to develop chickenpox after they’ve become infected.
Shingles during pregnancy
You can get shingles (herpes zoster) if you’ve had chickenpox. The chickenpox virus can stay in a person’s body for years after they’ve had chickenpox. Shingles is the reactivation of the chickenpox virus and you will notice a rash of blisters in just one place on your body.
Shingles blisters also have the chickenpox virus inside. So a person who has never had chickenpox can catch it from someone with shingles. This is very rare though and unlikely to happen if the blisters are covered with clothing, for instance.
What effect does chickenpox have on pregnant women?
Chickenpox is much more serious in adults, especially pregnant women, because their hormone levels are altered and their immune system works differently. Pregnant women appear to be at greatest risk late in the second trimester or early in the third trimester. If you suspect you have chickenpox or you’ve been exposed to it, contact your midwife or doctor as soon as possible so that they can make arrangements for appropriate tests or treatment.
If you have chickenpox when you’re due to give birth, you’ll be isolated by the hospital so you don’t infect other women.
What effect does chickenpox have on an unborn child?
Any effects are very rare, but unfortunately they can be very serious. There is around a 1% incidence of foetal varicella syndrome if a woman contracts chickenpox in the first 12 weeks of pregnancy, and around a 2% incidence between 13 and 20 weeks. Foetal varicella syndrome can cause problems with limb growth, brain development, and overall growth. It can also cause skin scarring and cataracts. A large number of babies who develop the syndrome are likely to die. Infection after 20 weeks has a lower risk of harm, but there have been a few reports of harm after infection at up to 28 weeks.
What effect does chickenpox have on newborn babies?
If a woman has chickenpox seven days before she gives birth or within seven days after birth, her baby may get neonatal chickenpox. This can be very serious.
Babies who have chickenpox in the first seven days of life probably caught it when they were inside their mum. When babies are exposed to chickenpox after they are born they may be slightly more at risk than older children but deaths are rare. In such cases, the infection would begin between seven and 28 days after birth. Breastfeeding will help protect a baby. If mum is immune herself she will pass her antibodies to her baby. If she isn’t immune, she will probably catch the disease and share her antibodies with her baby through her breastmilk.
How does chickenpox affect women who are breastfeeding?
If a woman is already immune she cannot give chickenpox to her baby. If a woman isn’t immune and she gets chickenpox, her baby will be likely to catch chickenpox from her. If she is breastfeeding, her baby will receive help in fighting the infection through the antibodies in her milk (the infection cannot be passed on through breastmilk).
What about prevention and protection?
Two vaccines are available in the UK but the Joint Committee on Vaccination and Immunisation has recommended that these should only be used for non-immune healthcare workers in contact with at-risk members of the public, and close household contacts of immunosuppressed individuals. If you wish to have the vaccine you would have to be tested first to see if you’re immune and then you would have to pay for a private course of vaccinations, as two doses are required. You would have to wait at least three months after the second dose before becoming pregnant.
The vaccine is not normally provided under the NHS unless you’re in one of the two identified groups of people. If you’re pregnant and know you’re not immune, avoid contact with anyone who may be infected.
If you’re pregnant and have been in contact with someone who has chickenpox, and you believe you may not be immune, visit your doctor as soon as possible. Your doctor can then arrange a blood test to see if you’re immune, and if you aren’t, you can be given human varicella-zoster immunoglobulin. It won’t prevent chickenpox but it will make the illness less serious, and it will only work for a short time.
The immunoglobulin needs to be given within 10 days of a pregnant woman coming into contact with chickenpox during her pregnancy but within seven days if she develops chickenpox within seven days before or after the birth. Her baby will also need to be given it if they’re exposed to chickenpox in the first seven days of their life and they have no antibodies from their mum.
What is the treatment?
The drug, acyclovir, is used to treat chickenpox and reduce the severity of the disease. It must be started within 24 hours of the rash beginning. It’s likely to be given to a baby who develops chickenpox despite having had human varicella-zoster immunoglobulin.
Paracetamol can be used in the early stage to reduce a temperature and calamine lotion applied to the rash may help with itching. Contact your local pharmacist for further advice. Remember that aspirin shouldn’t be given to anyone under the age of 16.
NCT's helpline offers practical and emotional support with all aspects of being pregnant, birth and early parenthood: 0300 330 0700. We also offer antenatal courses which are a great way to find out more about birth, labour and life with a new baby.
The Royal College of Obstetricians and Gynaecologists published its latest guidelines on managing chickenpox in pregnancy in January 2015. Read its advisory leaflet 'Chickenpox when you are pregnant: What you need to know'.