Most of the time you need not be worried if you’ve been exposed to chicken pox while you are pregnant. If you’ve already had the chicken pox your body has developed antibodies to the virus, which normally makes you immune to the disease. Even if you don’t remember having the chicken pox, research shoes that about 95% of adults born and raised in the United States are immune.
If you do catch the chicken pox while you are pregnant there is a very small chance that it will affect your baby and a slight possibility that it could be dangerous to you. If you contract chicken pox during the first half of pregnancy there is a 1 to 2 percent chance that your baby could get congential varicella syndrome, which causes birth defects and serious abnormalities. In a small amount of cases, it can cause miscarriage. You’ll probably have an ultrasound between 18 and 20 weeks to see if there are any signs of defects.
If you catch the chicken pox in the second half of your pregnancy, but at least five days before giving birth, your baby will get the antibodies that your body makes against the virus, offering protection to the baby. It is possible your baby may develop chicken pox after he is born, but it is unlikely to be serious because of the antibodies you passed on to the baby. Sometimes babies exposed to chicken pox before birth develop shingles during infancy or childhood, but this is also usually not serious.
If you develop a case of the chicken pox five days before delivery, or up to two days after delivery then your baby has a 30 to 40 percent chance of developing neonatal varicella (newborn chicken pox). Newborn can be serious or life threatening, especially if left untreated. There are treatments available that can reduce serious cases that include blood products with chicken pox antibodies and the antiviral drug acyclovir.
If you have been exposed to chicken pox and are not sure if you are immune to the virus, you should call your doctor or midwife. They can run a simple blood test to check for antibodies for the chicken pox virus.