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Chicken Pox & Pregnancy
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How long should a woman wait to become pregnant after receiving varicella vaccine?
The ACIP and the AAP recommend that a woman not become pregnant for at least one month following each dose of the vaccine. This differs from the package insert, which recommends a three month delay.
What is congenital varicella syndrome?
Fetal infection after maternal varicella in the first or early second trimester of pregnancy may result in varicella
embryopathy, characterized by limb atrophy and scarring of the skin of the extremity, known as congenital varicella syndrome. Other manifestations include central nervous system and eye abnormalities.
What is the risk of congenital varicella syndrome?
Data from a prospective study of 1700 women who contracted varicella during pregnancy has provided the following risks of congenital varicella syndrome: 0.4% for infection from 0 to 12 weeks of pregnancy and 2.0% for infection from 13 to 20 weeks of pregnancy.
If a woman receives varicella vaccine and subsequently finds out that she is pregnant, what should she be told about the risk to the fetus?
Since the risk of congenital varicella syndrome following natural infection is 0.4-2.0%, the risk of congenital anomalies following vaccination with attenuated varicella vaccine is likely to be lower or absent. In order to clarify this risk, Merck and Co., Inc., in collaboration with CDC, has established a Varicella Vaccine in Pregnancy Registry, similar to that which was established for rubella vaccine during pregnancy. So far, there have been no cases of congenital varicella syndrome reported to the registry however the number of women followed so far precludes excluding a very low risk. We encourage enrollment of women who were given varicella vaccine inadvertently during pregnancy. Women may be enrolled in the registry by calling 1-800-986-8999.
Should children and susceptible persons living in a household with a susceptible pregnant woman be vaccinated ?
Yes, susceptible children living in a household with a susceptible pregnant woman should be vaccinated. Pregnant women who have never had chickenpox are at risk of getting chickenpox during pregnancy. A small percentage of women who get chickenpox in the first or second trimester can have babies with birth defects known as "congenital varicella syndrome." In addition, chickenpox may be more severe in pregnant women than in others putting the woman at risk of severe complications Vaccinating close contacts of a susceptible pregnant woman is the most effective way to protect her from disease. Although there is a small risk that a vaccinated person could get a vaccine rash and spread the vaccine strain virus to the pregnant woman, this risk is much smaller than the risk that she could contract "natural" varicella.
As soon as the pregnant woman delivers her baby, she should be vaccinated against varicella. The first dose of vaccine can be given before she is discharged from the hospital and the second dose at the 6-week post-partum visit.
How should a pregnant woman with varicella be advised and treated?
The woman should be advised that the risk of congenital varicella syndrome is relatively low (0.4% for infection 1-12 weeks of pregnancy and 2.0% for infection 13-20 weeks of
pregnancy). The safety of systemic acyclovir therapy among pregnant women has not been established. Although studies involving animals have not indicated teratogenic effects of acyclovir, adequate, well-controlled studies among pregnant women have not been conducted. Acyclovir is classified as Category C in the FDA use-in-pregnancy rating (i.e., risk cannot be ruled out, but potential benefits may justify the possible risk) (Burroughs Wellcome Company, Zovirax package insert). AAP does not recommend oral acyclovir for pregnant women; however, in instances of serious, viral-mediated complications (e.g., pneumonia), AAP states that intravenous acyclovir should be considered. Burroughs Wellcome Company, in collaboration with CDC and academic epidemiologists, maintains the Acyclovir in Pregnancy Registry to monitor the maternal-fetal outcomes of pregnant women who have received systemic acyclovir. Physicians are encouraged to register pregnant patients who are being treated with acyclovir by calling (800) 722-9292, ext. 58465.
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