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(Date of issue: November 2016, Version: 2)

This is a UKTIS monograph for use by health care professionals. For case-specific advice please contact UKTIS on 0344 892 0909. To report an exposure please download and complete a pregnancy reporting form. Please encourage all women to complete an online reporting form.


Chickenpox is an infection caused by the herpes varicella zoster virus (VZV).  VZV is highly contagious and transmitted by respiratory droplets and contact with vesicle fluid.  Pregnant women, particularly those >20 weeks gestation, may have a higher risk of severe complications following infection with VZV.

There is an up to 2% risk of fetal varicella syndrome following maternal infection with VZV during pregnancy.  Fetal varicella syndrome is characterised by skin scarring, eye defects, hypoplasia of the limbs and neurological abnormalities.  Perinatal exposure to VZV can result in severe neonatal varicella infection.

Maternal treatment with varicella zoster immunoglobulin or aciclovir may be given if clinically indicated. The varicella zoster vaccination should be avoided during pregnancy due to the theoretical risk of fetal infection.  There is currently no evidence of an increased risk of malformations following vaccination during pregnancy, although data are still too limited to exclude the possibility of an increased risk.

Inadvertent exposure to varicella zoster virus, immunoglobulin or vaccination at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy but may warrant enhanced antenatal surveillance of fetal growth and development. Other risk factors may also be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case specific risk assessments.

This document is regularly reviewed and updated. Only use full UKTIS monographs downloaded directly from to be sure you are using the most up-to-date version. The summaries of these monographs are openly available on

This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to health care professionals at

If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.

If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.

Disclaimer: Every effort has been made to ensure that this monograph was accurate and up-to-date at the time of writing, however it cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes of the measures recommended. The final decision regarding which treatment is used for an individual patient remains the clinical responsibility of the prescriber. This material may be freely reproduced for education and not for profit purposes within the UK National Health Service, however no linking to this website or reproduction by or for commercial organisations is permitted without the express written permission of this service. This document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from or to ensure you are using the most up-to-date version.