Chicken Pox in Pregnancy: Risks and Concerns

Question
Hi.  My 7 year old son just came down with the chicken pox today, despite
getting a vaccination @1 yr old.  It's going around his school.  My concern is
that I'm 35 weeks pregnant, and quite a few people I've encountered today,
have been really concerned for the baby, with me being exposed to chicken
pox.  I called my OB-GYN, and his nurse said not to worry about it, (because
my Mom said she believes I had chicken pox when I was 6 months old).  But, I
can't help but be concerned a little now, with the way friends and neighbors
are reacting.

Answer
Dear Karen,

If you've had chicken pox before, you're probably immune, so there's no need to worry. Up to 95% of adults in the U.S. are immune, including many people who had chicken pox and never even knew it. If you're not sure whether you're immune, a simple blood test can give you the answer.

IF you get chicken pox in the second half of pregnancy but more than five days before giving birth, your baby will probably be fine. Here's why: About five days after coming down with chicken pox, your body develops antibodies to the virus and passes them to your baby through the placenta, offering protection that his own immature immune system can't provide.

If you develop chicken pox 5-21 days before your baby is born, he might develop chicken pox days after birth, but because of the antibodies he received from you, it's much less likely to be serious. (Some babies exposed to chicken pox in utero, particularly those exposed 5-21 days before birth, develop a case of shingles during infancy or early childhood without having had chicken pox after birth, but it's usually not serious.)

The most risky time to come down with chicken pox is between 5 days before giving birth and 2 days after delivery, because then your baby is exposed to the virus but doesn't have had time to receive antibodies from you before birth. In this case, he has a 30-40% chance of developing what's called neonatal varicella, or newborn chicken pox, which can be quite serious, especially if left untreated. Fortunately, your baby's risk of a severe case can be greatly reduced if he gets a shot of varicella zoster immune globulin (VariZIG), a blood product that contains chicken pox antibodies. He'll be given the shot soon after birth if your chicken pox showed up within 5 days of delivery or as soon as you discover your rash if it's within 2 days after delivery.

But as I noted, almost all adults in the U.S. are immune. Make sure to watch for any signs of an active chicken pox infection and let your doctor know if you experience any. It can take anywhere from 10-21 days after exposure, though most often you'll see signs 14-16 days after being exposed. For the first day or two, you may have mild flu-like symptoms, followed by an itchy rash. The rash starts out as little red bumps that blister as they get larger, then eventually dry out and scab over. You'd probably see it first on your face, chest, or abdomen, and new eruptions will gradually appear on other parts of your body. You're contagious from about 48 hours before the first crop of bumps appears until they've all crusted over.

Otherwise, relax and let all the well-meaning, yet overly concerned, friends and neighbors fret by themselves.   :-)

I hope this information has helped you and answered your question. I wish you well!

Brenda