If you have had chickenpox and are therefore immune to the disease, contact with the virus will not pose a risk to any pregnancy of yours. A baby in your womb will be protected by your antibodies. There is only a risk to the baby when a woman who is not immune to chickenpox develops the disease in pregnancy. If you have any doubt about whether you have had chickenpox or not, you could request a blood test to establish whether or not you are immune. If you are not immune to chickenpox, then there is a risk that you might contract this infection. However, the time of greatest risk to your baby is in the first 12-16 weeks of pregnancy, and this has now passed.
For adults, though, chickenpox can be a serious illness and it tends to be worse in pregnancy. For this reason, women who are not immune to the infection, and who come into contact with it, should be given a substance called zoster immunoglobulin which provides them with resistance against the disease.
If a pregnant woman does develop chickenpox, there is a drug called acyclovir, an antiviral medication, which can be used in the second half of pregnancy, and this is thought to reduce the severity of the infection. There is a theoretical risk of developmental abnormalities in the baby when this drug is used in the first 12 weeks, and for this reason acyclovir should be avoided during that period. Even if you are not immune and you do contract chickenpox, it is very unlikely that your baby will be affected by this infection.