Chickepox and the Pregnant Woman

mother holding her daughter who has chickenpox
What do you need to know about chickenpox during pregnancy?. Photo©monkeybusinessimages

If you are exposed to or develop chickenpox while you are pregnant, there are a few important things you should know about how the infection could affect you and your unborn baby. There are also steps you can take to protect yourself from the varicella virus before, during, and after delivery.

Chickenpox in Pregnancy

Chickenpox is a viral infection caused by the varicella virus. For most people, the virus causes a benign, self-limited illness. However, when chickenpox is acquired during pregnancy, it can cause an increased risk of serious complications for the mother and the infant.

The time of infection (whether during early pregnancy or near delivery) plays a significant role in the risk that chickenpox poses to a mother and baby.

Pregnant Women Exposed to Chickenpox

Pregnant women who have a history of a previous chickenpox infection or who have been immunized will have antibodies to the virus. Therefore, they are typically not susceptible to getting the infection again. The antibodies are transferred to the infant through the placenta throughout pregnancy.

If a pregnant woman is immune and gets exposed to someone who has chickenpox, they do not need to worry about complications for themselves or their infant.

Often times, a varicella titer will be offered during pregnancy to confirm prior infection.

However, women who are susceptible to chickenpox (either because they have never had the infection or have not been immunized) are at risk.

If you believe that you have been exposed to chickenpox while pregnant call your doctor right away. If you are not immune to varicella but are exposed to the virus, it's possible to be treated with varicella-zoster immunoglobulin (VZIG), an antibody to provide passive immunization.

Testing for Immunity in Pregnancy

Pregnant women should be questioned about previous chickenpox infection or immunization at their first prenatal visit. However, testing for antibodies against chickenpox as evidence of immunity is controversial.

Of the women who do not remember having a past infection or immunization, 80 to 90% have antibodies and are considered immune. Still, many practitioners do obtain the test at the first prenatal visit.

Vaccination against chickenpox during pregnancy is not recommended.

The chickenpox vaccine is a live virus vaccine. It carries the theoretical risk of causing an infection, especially in those who are immunosuppressed or pregnant.

Maternal Complications of Chickenpox in Pregnancy

Most women of childbearing age have immunity to the varicella virus (because of a previous infection or immunization). Primary chickenpox infection is rare, occurring in only 0.05 to 0.07% of pregnancies.

Women who do acquire chickenpox while pregnant, especially in the third trimester, are at a greater risk of developing varicella pneumonia. Varicella pneumonia is a potentially life-threatening infection of the lungs by the varicella virus.

Infant Complications of Chickenpox in Early Pregnancy

Primary chickenpox infection in the first trimester of pregnancy (especially from weeks 8 to 12) carries a 2.2 % risk of congenital varicella syndrome.

Manifestations of congenital varicella syndrome include:

  • Low birth weight
  • Mental retardation
  • Microcephaly (a smaller than normal head)
  • Scarring of the skin
  • Vision problems

Infant Complications of Shingles in Pregnancy

Shingles is a condition caused by the re-activation of the chickenpox virus. It can occur at any time following the original infection. After a primary varicella infection clears, the virus remains dormant. However, it can reactivate, especially when the body is immunosuppressed.

While we don't hear as much about the potential impact of shingles on pregnancy, a 2016 study found that of 130 women who delivered infants with congenital varicella syndrome, 2 of the cases were related to shingles rather than primary chickenpox infections.

Recognizing the early signs and symptoms of shingles is important for everyone, but especially pregnant women. Treatment for shingles is available and can reduce the condition's severity, but only when it is started within the first few days of illness.

Infant Complications of Chickenpox in Late Pregnancy

Disseminated varicella infection occurs when the virus infects a newborn before the transfer of protective maternal antibodies has taken place.

If a pregnant woman gets a primary chickenpox infection during the period 7 days before until 7 days after delivery, her newborn is at risk for disseminated varicella infection.

Treatment of Pregnant Women With Chickenpox

Women who acquire a primary chickenpox infection during pregnancy should be treated with the antiviral drug Zovirax (acyclovir,) a medication which appears to have a good safety profile in pregnancy. 

Pregnant women who develop varicella pneumonia should be observed in the hospital and treated with intravenous acyclovir.

Treatment of Infants With Chickenpox

Infants whose mothers develop varicella 5 days before delivery or 2 days following delivery should receive varicella-zoster immunoglobulin (VZIG) after birth.

Newborns who develop varicella during the first 2 weeks of life should be treated with intravenous acyclovir.

Postpartum Vaccination

If a woman is found to be non-immune to chickenpox during pregnancy (and does not develop the disease during pregnancy) she should be immunized during the postpartum period. This helps prevents the risk of infection in later pregnancies.

Bottom Line

If you develop (or are even exposed to) chickenpox while you are pregnant, it can be very unsettling. You may have heard frightening things about how chickenpox can affect unborn babies or newborns.

While there are risks to developing varicella infections when you are pregnant, there are also many things that can be done to reduce these risks for both yourself and your baby. Should they occur, chickenpox infections in pregnancy can be treated.

If you are planning a pregnancy, talk to your doctor about whether you have had the chickenpox or received an immunization. If your immune status is unknown, a blood test can be done to check. You may be tested at your first prenatal visit and you can get vaccinated if needed.

If you already know that you are not immune to the chickenpox and are planning to get immunized, it is recommended that you do so at least 3 months before you get pregnant.

If you are pregnant and have been exposed to the chickenpox virus, call your doctor immediately. Preventative measures are most effective when employed as soon as possible after exposure and long before any symptoms develop.

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Article Sources
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