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Infections During Pregnancy

Varicella Zoster Virus Infection in Pregnancy

Varicella zoster virus (VZV) causes chickenpox as primary infection and shingles as reactivation of latent infection. In pregnancy, the main clinical priorities are determining maternal immunity after exposure, preventing or modifying severe maternal disease when possible, recognizing maternal pneumonia or other complications, assessing fetal risk after maternal infection, and preventing severe neonatal varicella when maternal rash occurs near delivery.

Updated: June 9, 2026. This page is for clinical education and should not replace individualized medical care, local infection-control policies, or consultation with maternal-fetal medicine, infectious disease, pediatrics/neonatology, or public health when indicated.

Cause and overview

Varicella zoster virus is a highly contagious DNA herpesvirus. Primary infection causes varicella, commonly called chickenpox. After primary infection, VZV remains latent in sensory nerve ganglia and may later reactivate as herpes zoster, also called shingles.

Varicella zoster virus exposure and acute illness pathway in pregnancy Original educational schematic showing VZV exposure or rash, immunity assessment, VariZIG pathway for susceptible exposure, acute varicella diagnosis, maternal severity assessment, oral antiviral treatment for uncomplicated disease, IV acyclovir for severe disease, fetal ultrasound follow-up, and neonatology notification when rash occurs near delivery. Varicella in Pregnancy Patient reports VZV exposure or rash Exposure only Confirm significant contact + timing Rash present Isolate; diagnose clinical ± PCR Check immunity History, vaccine or VZV IgG Immune Reassure; no PEP Nonimmune VariZIG ASAP within 10 days Assess severity Pneumonia, hypoxia, CNS signs, hepatitis Uncomplicated Isolation + supportive care; consider oral acyclovir/valacyclovir Severe Hospital evaluation + IV acyclovir if pneumonia/CNS/etc. Early pregnancy Counsel low but important risk of fetal varicella syndrome; MFM US Detailed US Growth, limbs, brain, eyes, calcifications, hydrops Rash near delivery Notify neonatology Delivery plan Individualize; avoid planned delivery ~7 days
Expanded overview graphic. PEP = post-exposure prophylaxis; VZV IgG = varicella-zoster virus IgG; US = ultrasound; CNS = central nervous system.
Incubation
The incubation period is usually 10–21 days, with an average of approximately 14 days.
Infectious period
A person with chickenpox is generally infectious from 1–2 days before rash onset until all lesions have crusted.
Clinical syndrome
Chickenpox causes fever, malaise, and a pruritic rash that evolves from macules and papules to vesicles, pustules, and crusts in successive crops.
Pregnancy relevance
Adults, including pregnant patients, are at higher risk than children for severe varicella, especially varicella pneumonia.

Epidemiology and transmission

Varicella is transmitted by respiratory droplets, airborne spread from infected respiratory secretions, and direct contact with vesicular fluid. Household exposure is particularly efficient. Most adults in the United States have evidence of immunity from prior infection or vaccination, so primary varicella in pregnancy is uncommon; however, disease in a susceptible pregnant patient can be serious.

Exposure source Pregnancy relevance
Chickenpox Highly contagious. Significant exposure includes household contact, face-to-face contact, or prolonged indoor contact with an infectious person.
Shingles Localized covered shingles is less infectious than chickenpox, but exposed lesions, disseminated zoster, or zoster in an immunocompromised person may transmit VZV to a susceptible contact.
Healthcare exposure Requires prompt infection-control review to protect susceptible pregnant patients, neonates, immunocompromised patients, and susceptible healthcare personnel.
History matters: A reliable history of prior chickenpox, shingles, or two documented varicella vaccine doses generally indicates immunity. If history is absent, uncertain, or considered unreliable, obtain VZV IgG promptly after significant exposure.

Clinical algorithm: exposure or acute varicella in pregnancy

This workflow separates two common clinical scenarios: a pregnant patient with exposure but no rash, and a pregnant patient who has already developed acute varicella. Management depends on immunity, exposure timing, gestational age, maternal severity, and timing relative to delivery.

International note: UK/RCOG post-exposure approach

International note: RCOG/UKHSA approach: RCOG/UKHSA guidance differs from the U.S. CDC-centered approach. In the UK, oral antiviral post-exposure prophylaxis is recommended as first choice for susceptible pregnant patients after significant exposure: acyclovir 800 mg orally four times daily from day 7 to day 14 after exposure, or valacyclovir 1,000 mg orally three times daily from day 7 to day 14 after exposure. VZIG may be considered when antivirals are contraindicated or not tolerated.

Determining immunity after exposure

Finding Interpretation Action after significant exposure
Documented two-dose varicella vaccine series Evidence of immunity. Reassure; no VariZIG needed.
Reliable history of chickenpox or shingles Usually evidence of immunity. Reassure; no VariZIG needed unless immunocompromised or history is unreliable.
Positive VZV IgG Immune. Reassure; no post-exposure prophylaxis needed.
Negative VZV IgG Susceptible. Consider post-exposure prophylaxis when exposure is significant.
Unknown status and testing unavailable promptly Manage based on exposure severity and local protocol. Do not delay clinically indicated post-exposure prophylaxis while awaiting delayed testing.

Diagnosis of Varicella in the Mother

Varicella lesions on the face

Varicella usually causes a typical skin eruption. The lesions begin as raised red papules that progress quickly to clear vesicles. The vesicles then become cloudy pustules and, subsequently, dry to form crusted lesions. The lesions usually begin on the face and trunk and spread centripetally to the extremities. The lesions are intensely pruritic and occur in crops.

Adult patients usually have systemic manifestations such as malaise, fatigue, and fever. Tachypnea, cough, chest pain, hypoxia, or dyspnea may signal varicella pneumonia, which can be complicated by superimposed bacterial infection. Headache, photophobia, altered mental status, or focal neurologic findings should raise concern for encephalitis.

The diagnosis of acute varicella infection can usually be established clinically. If laboratory confirmation is needed, polymerase chain reaction (PCR) testing from vesicular fluid, scabs, or lesion material is preferred. Serology may be useful in selected cases, but varicella IgM testing is less reliable than PCR for confirming acute disease.

Click image to enlarge. Image credit: Copyright © 2007 Interactive Medical Media LLC, All rights reserved.

Urgent evaluation: Pregnant patients with suspected varicella should be evaluated promptly if they develop respiratory symptoms, hypoxia, persistent fever, neurologic symptoms, dehydration, or clinical deterioration.

Post-exposure prophylaxis

United States approach: CDC recommends VariZIG for exposed patients without evidence of immunity who are at high risk for severe varicella and for whom varicella vaccine is contraindicated, including pregnant patients. VariZIG should be given as soon as possible after exposure and can be given within 10 days. See also: Perinatology.com OBRx: VariZIG .
Situation Suggested management
Immune pregnant patient after exposure No prophylaxis; reassure and advise patient to report symptoms if rash develops.
Nonimmune pregnant patient with significant exposure Offer VariZIG as soon as possible and within 10 days of exposure according to CDC guidance.
VariZIG unavailable or delayed Discuss with infectious disease or public health. Some protocols consider antiviral prophylaxis, but recommendations vary by country and institution.
Rash has already developed VariZIG is not treatment. Manage as acute maternal varicella.

Acute maternal varicella

Acute varicella is usually diagnosed clinically by the characteristic pruritic vesicular rash in different stages of evolution. If laboratory confirmation is needed, PCR testing of vesicular fluid or lesion material is preferred.

Clinical issue Recommended approach
Uncomplicated chickenpox Symptomatic care, isolation, avoidance of susceptible contacts, and consideration of oral acyclovir or valacyclovir, especially in the second or third trimester and when started early.
Respiratory symptoms Urgent evaluation for varicella pneumonia. Symptoms include cough, dyspnea, tachypnea, hypoxia, chest pain, or clinical deterioration.
Severe or complicated disease Hospital evaluation and IV acyclovir. Severe complications include pneumonia, hepatitis, encephalitis, disseminated disease, or significant maternal clinical deterioration.
Delivery timing Individualize. If maternal varicella occurs near term and maternal/fetal status allows, delaying planned delivery may permit maternal antibody transfer before birth.
Urgent maternal warning signs: dyspnea, cough, chest pain, hypoxia, persistent fever, neurologic symptoms, severe headache, photophobia, dehydration, or rapidly progressive rash.

Fetal risk and ultrasound evaluation

Congenital varicella syndrome is rare but can occur after maternal primary varicella infection, especially in the first half of pregnancy. Reported risk is low, approximately 0.4% after first-trimester infection and up to approximately 2% after infection in the second trimester in older series.

Maternal infection timing Fetal/neonatal concern Suggested follow-up
Before 20 weeks Low but important risk of fetal varicella syndrome: limb hypoplasia, cicatricial skin scarring, microcephaly, cortical atrophy, ventriculomegaly, chorioretinitis, cataracts, growth restriction, and neurologic sequelae. Maternal-fetal medicine referral and detailed ultrasound, commonly at least 5 weeks after infection or at 16–20 weeks.
20–28 weeks Fetal varicella syndrome is uncommon but counseling and ultrasound assessment remain appropriate. Detailed ultrasound and individualized follow-up.
Late pregnancy but not near delivery Congenital varicella syndrome is not the primary concern; neonatal risk depends on timing relative to delivery. Routine obstetric care unless maternal disease or fetal findings indicate otherwise.
5 days before to 2 days after delivery Highest risk period for severe neonatal varicella due to inadequate time for maternal antibody transfer. Notify neonatology urgently; neonatal prophylaxis and management per pediatric guidance.
Role of amniocentesis

Amniotic fluid VZV PCR can detect fetal infection, but a positive result does not reliably predict fetal injury or severity. Ultrasound remains the principal tool for evaluating fetal structural effects. Amniocentesis should be individualized after counseling and is generally not performed until maternal skin lesions have healed.

Neonatal varicella risk

Neonatal risk is greatest when maternal varicella rash occurs from 5 days before delivery to 2 days after delivery. During this interval, the neonate may be exposed before adequate transplacental maternal antibody transfer has occurred.

Timing Clinical implication
Maternal rash >7 days before delivery Maternal antibody transfer is more likely; neonatal disease risk is generally lower, but neonatology should still be informed.
Maternal rash 5 days before to 2 days after delivery Highest-risk window for severe neonatal varicella; notify neonatology immediately.
Maternal rash after delivery Neonate may require prophylaxis and close follow-up depending on timing and exposure details.
Neonatology notification: Inform pediatrics/neonatology of any maternal varicella infection during pregnancy, and urgently if rash occurs near delivery.

Vaccination

Clinical situation Recommendation
Pregnant patient Varicella vaccine is contraindicated during pregnancy because it is a live attenuated vaccine.
Nonpregnant person without evidence of immunity CDC recommends two doses of varicella vaccine for those without evidence of immunity unless contraindicated.
Postpartum susceptible patient Vaccinate postpartum before discharge when feasible; breastfeeding is not a reason to delay vaccination.
After vaccination Avoid pregnancy for 1 month after each varicella vaccine dose.

EMR-ready counseling text

Exposure to chickenpox or shingles

Varicella zoster virus exposure in pregnancy was reviewed. Exposure history was assessed, including source illness, timing, duration, and proximity. Maternal immunity should be determined by reliable history of prior chickenpox/shingles, documentation of two varicella vaccine doses, or VZV IgG testing if history is uncertain. If the patient lacks evidence of immunity and exposure is significant, post-exposure prophylaxis is recommended according to current CDC/local guidance. In the United States, VariZIG is recommended for susceptible high-risk exposed patients, including pregnant patients, as soon as possible and within 10 days after exposure. Patient was advised to report fever or rash immediately and to avoid exposing susceptible pregnant patients, neonates, and immunocompromised individuals if symptoms develop.

Acute varicella infection in pregnancy

Acute varicella infection in pregnancy was reviewed. Maternal risks include severe varicella, pneumonia, hepatitis, encephalitis, hospitalization, and rarely death. Patient should be isolated from susceptible contacts until lesions have crusted. Oral acyclovir or valacyclovir may be considered for uncomplicated disease, especially in the second or third trimester and when treatment can be started early. IV acyclovir is recommended for severe or complicated disease, including suspected varicella pneumonia. Warning signs requiring urgent evaluation include cough, dyspnea, chest pain, hypoxia, persistent fever, neurologic symptoms, dehydration, or clinical deterioration.

Fetal and neonatal counseling

Fetal and neonatal risks of maternal varicella were reviewed. Congenital varicella syndrome is rare but may occur after primary maternal infection in early pregnancy and can include limb hypoplasia, cicatricial skin scarring, ocular abnormalities, microcephaly, ventriculomegaly, growth restriction, and neurologic sequelae. Recommend maternal-fetal medicine referral and detailed ultrasound evaluation after maternal infection. If maternal rash occurs from 5 days before to 2 days after delivery, neonatal varicella risk is increased; pediatrics/neonatology should be notified urgently for newborn prophylaxis and management.

Susceptible patient: postpartum vaccination

Patient lacks evidence of varicella immunity. Varicella vaccine is contraindicated during pregnancy. Postpartum varicella vaccination was recommended, and breastfeeding is not a contraindication. Pregnancy should be avoided for 1 month after each vaccine dose.

Archived prior page: Diagnosis and Management of Varicella Infection in Pregnancy

References

  1. American College of Obstetricians and Gynecologists. Cytomegalovirus, Parvovirus B19, Varicella Zoster, and Toxoplasmosis in Pregnancy. Practice Bulletin No. 151. Obstet Gynecol. 2015;125:1510-1525. Reaffirmed 2017. ACOG page.
  2. Royal College of Obstetricians and Gynaecologists. Chickenpox in Pregnancy. Green-top Guideline No. 13. January 2015; minor update 2024. RCOG guideline.
  3. Bhavsar SM, Agarwal A, Lewis R, Ganta S. Congenital Varicella Syndrome. StatPearls. NCBI Bookshelf. NCBI Bookshelf.
  4. Saleh HM, Ayoade F, Kumar S. Varicella-Zoster Virus (Chickenpox). StatPearls. NCBI Bookshelf. NCBI Bookshelf.
  5. Centers for Disease Control and Prevention. Clinical Overview of Chickenpox (Varicella). CDC clinical overview.
  6. Centers for Disease Control and Prevention. Clinical Guidance for People at Risk for Severe Varicella. CDC clinical guidance.
  7. Centers for Disease Control and Prevention. Updated Recommendations for Use of VariZIG — United States, 2013. MMWR. 2013;62:574-576. CDC MMWR.
  8. Perinatology.com. OBRx Antivirals: VariZIG. Perinatology OBRx VariZIG.
  9. Centers for Disease Control and Prevention. Guidelines for Vaccinating Pregnant Women. CDC pregnancy vaccine guidance.
  10. Centers for Disease Control and Prevention. Varicella Vaccination for Specific Groups. CDC vaccine guidance.
  11. Lamont RF, Sobel JD, Carrington D, et al. Varicella-zoster virus chickenpox infection in pregnancy. BJOG. 2011;118:1155-1162. PubMed.
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