Varicella Infection In Pregnancy - Consequences For Foetus And Neonate

Patient Education

What would happen to my baby if I got chickenpox while I'm pregnant?

Chances are good that no harm would come to your baby, but timing is a factor. If you get chickenpox during the first or second trimester of pregnancy, there's a slight risk (probably less than 2 percent overall) that your baby will get something called congenital varicella syndrome (CVS). The risk is highest if you're infected between 13 and 20 weeks' gestation.

CVS is characterized by birth defects, most commonly skin scarring, malformed limbs, an abnormally small head, neurologic problems (like intellectual disability), and vision problems. Plus, a baby with CVS may also grow poorly in utero and suffer from seizures and physical and mental developmental disabilities. The infection may also increase the risk of miscarriage or later fetal death.

If you do contract chickenpox, you'll have a detailed ultrasound to look for signs of defects or other problems and at least one follow-up sonogram to see how your baby is doing later on.

Is my baby at risk if I get chickenpox close to my due date?

If you get chickenpox early in the third trimester of pregnancy, your baby will probably be fine. Here's why: About five days after you come down with chickenpox, your body develops antibodies to the virus and passes them to your baby through the placenta, offering protection that his own immature immune system couldn't provide on its own.

If you develop chickenpox five to 21 days before your baby is born, he might develop chickenpox, but because of the antibodies he received from you, it's much less likely to be serious. (Some babies exposed to chickenpox in utero don't have any signs of infection at birth but develop a case of shingles during infancy or early childhood without having had chickenpox. Fortunately, it's usually not serious.)

The riskiest time to come down with chickenpox is between five days before giving birth and two days after delivery, because when your baby is exposed to the virus but doesn't have time to receive antibodies from you. In this case, there's a high chance (estimated at 17 to 30 percent) that he'll develop what's called neonatal varicella, or newborn chickenpox, which can be serious and even life-threatening - 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 (VZIG), a blood product that contains chickenpox antibodies. Your baby will be given the shot soon after birth if your chickenpox showed up within five days of delivery or as soon as you discover your rash if it's within two days after delivery.

If your newborn shows any sign of developing the infection, such as coming down with a fever or showing a rash or even a few spots, he'll be treated intravenously with the antiviral drug acyclovir.

What should I do if I'm exposed?

If you know you're immune, you don't need to do anything. If you're not sure or you think you're not immune, call your healthcare provider immediately and arrange to have a blood test to confirm your status.

If the blood test shows that you're not immune, you can get a shot of VariZIG to reduce your chances of severe infection and very serious complications. You can receive the shot up to ten days after being exposed to chickenpox, though it's best to get it as soon as possible. Unfortunately, the shot won't prevent fetal infection.

If I'm not immune and I get exposed, what are the chances I'll catch chickenpox?

Chickenpox is highly contagious, so if you've never had it before and you have direct contact with an infected person, you're very likely to get it. In fact, if someone in your household has chickenpox and you're not immune, chances are 90 percent that you'll catch it, too.

How soon would I see symptoms?

It can take anywhere from ten to 21 days after exposure, though most often you'll see signs after 14 to 16 days. At first, 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'll 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.

How can I reduce my risk of getting chickenpox during pregnancy if I'm not immune?

Avoid anyone who has or may have chickenpox. This includes anyone who's not immune and has come in contact with an infected person in the last three weeks, and anyone with flu-like symptoms (people with chickenpox are very contagious before they develop the telltale rash).

You'll also need to avoid contact with anyone with shingles. (People who've already had chickenpox develop shingles if the virus becomes reactivated.) Even though you can't catch shingles, you can catch the chickenpox virus from someone who has shingles.