Chickenpox and pregnancy – everything you need to know

Chickenpox is an almost-expected part of childhood – an irritating, but mild, condition. Unless, of course, you are pregnant. By Kim Bell

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According to Dr Villyen Motaze, of the Centre for Vaccines and Immunology at the National Institute for Communicable Diseases, globally almost 80% of people are infected with chickenpox by the age of 10.

What is chickenpox?

Dr Motaze explains that chickenpox is an infectious disease characterised by fever and a blister-type rash caused by varicella-zoster virus (VZV). It is highly contagious, and along with the trademark rash comes itching, fever and tiredness. However, once you have had it, you build an immunity towards it.

After recovery, the virus can lie dormant in a nerve root and reactivation of latent infection can cause shingles, a painful blister-like rash in the area supplied by that nerve. Shingles typically occurs later in life, on the face or trunk of the body, and either on the left or right side (not both).

The problem is that anyone can contract chickenpox if they have not had it previously, and the risk increases for those who attend schools or childcare facilities, or who work (or live) with children.

ALSO SEE: The benefits of vaccinations for children

Dr Motaze says that approximately 90% of close contacts who are non-immune will catch chickenpox after exposure. “A person with varicella is contagious from 1 to 2 days before rash onset until the sores have crusted. The incubation period is approximately 14 to 16 days after exposure to the virus. VZV can be spread from person to person through infected respiratory secretions (coughing, sneezing) that are aerosolised.” However, you can be exposed to the virus without experiencing the rash, which causes a form of “immunity”.

The best protection against chickenpox is vaccination, which has been available in the South African private sector since 2001. It consists of an initial vaccine between the ages of 12 and 15 months, with a follow up booster shot between the ages of four and six. The vaccine has been proven to be 90% effective in preventing chickenpox, and those who do get it, typically experience a milder case.

Chickenpox and pregnancy

It sounds innocuous, doesn’t it? But here’s the problem: it’s a childhood disease. Contracting chickenpox as an adult is already dangerous, as pneumonia is a relatively common complication. Contracting it as pregnant woman makes the situation more concerning.

If you catch chickenpox within the first two trimesters, there is a small (around 2%) risk that your baby could develop congenital varicella syndrome (CVS), which has a number of serious side effects including scarring, malformed limbs, an abnormally small head (usually accompanied by developmental concerns), seizures, vision problems, low birth weight and in severe cases, miscarriage or stillbirth.

If you are exposed in your third trimester, closer to the end of your pregnancy, your baby is likely to be fine as your body reaction to fighting off the illness is creating immune-boosting antibodies, which in turn will be passed onto your unborn baby.

However, chickenpox around your due date is much riskier. You may pass on the virus to your baby, but deliver before you are able to pass on the immune-building antibodies. In this case, your baby has no ability to fight the condition. This is called neonatal varicella, and can affect up to 30% of babies born to moms who have contracted chickenpox shortly before birth. As with adults, these babies are more prone to pneumonia, hepatitis and encephalitis.

ALSO SEE: South Africans urged to ensure all vaccines are up to date

What you can do

  • If you have had chickenpox as a child, or have been vaccinated yourself, you should be fine if exposed as you have built up immunity.
  • However, pregnant women who haven’t had chickenpox or haven’t been vaccinated should avoid contact with those who have chickenpox. If you do get chickenpox, contact your healthcare practitioner immediately. According to experts, you can be given acyclovir, an antiviral agent, if you see your doctor within 24 hours of the onset of the rash and are over 20 weeks pregnant.
  • Newborn babies of mothers with chickenpox can be given an immunoglobulin preparation, called Varicella Zoster Immune Globulin (VZIG), through an intramuscular injection to provide immediate protection. This special preparation is produced by the KwaZulu-Natal Blood Transfusion Service and is created from blood donated by people with high antibody levels to the chickenpox virus. However, it is a scarce commodity.
  • Planning to fall pregnant? If you can’t recall having chickenpox as a child, you can be tested for antibodies to determine your immunity. If you are not immune, it is recommended that you get the vaccine. This is available in the private sector as a monovalent vaccine, or co-formulated with other live-attenuated vaccines like measles, mumps and rubella. However, it is recommended that you avoid falling pregnant for at least three months after the vaccine. You cannot be vaccinated if you are already pregnant.

But before you panic, Dr Motaze shares that most adults in South Africa are immune to chickenpox as they would have been exposed as a child.

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