• Perform a general assessment to establish the woman's risk of chickenpox, on the basis of her history of chickenpox, the certainty of chickenpox in the contact, and the level of exposure.
• If the woman has a definite history of chickenpox or shingles, reassure her that she is not at risk of chickenpox because immunity can be assumed.
• If the woman has no history of chickenpox or shingles (or is uncertain) and has a history of significant contact:
• Establish the stage of gestation (weeks from the last menstrual period).
• Test for varicella-zoster immunoglobulin G (IgG) antibodies in primary care if test results can be available within 2 working days of first exposure. If this is not possible, urgently seek specialist advice because testing in secondary care and/or varicella-zoster immunoglobulin (VZIG) prophylaxis may be needed.
• If the test shows varicella-zoster immunoglobulin G, reassure the woman that she is immune and cannot catch chickenpox.
• If the woman's antibody status is negative, urgently seek specialist advice regarding the need for VZIG.
• Advise the woman to promptly seek advice from her doctor or midwife if she develops a rash and has had contact with chickenpox, regardless of whether she has received VZIG.

• Because chickenpox is a common childhood disease, more than 90% of pregnant women are immune. Therefore, although contact with chickenpox in pregnancy is common, primary infection is not (an estimated 3 in 1000 pregnancies are complicated by primary varicella-zoster infection) [RCOG, 2007].
• Women from tropical and subtropical areas are more likely to be seronegative for varicella-zoster immunoglobulin G and are therefore more likely to develop chickenpox [RCOG, 2007].

This recommendation is based on Department of Health guidance on the management of exposure to varicella [DH, 2006], guidance from the Health Protection Agency on the management of rash illness in pregnancy [HPA, 2007a], and guidance from the Royal College of Obstetricians and Gynaecologists on chickenpox in pregnancy [RCOG, 2007]:

• CKS suggests testing for varicella-zoster immunoglobulin G antibodies in primary care if the results can be available within 2 working days of first exposure (to allow time for referral to secondary care if necessary), taking into account the Royal College of Obstetricians and Gynaecologists guideline on Chickenpox in Pregnancy [RCOG, 2007], which states that if the woman's immune status is unknown, the administration of VZIG can be delayed until serology results are available, if the laboratory turnaround time is 24–48 hours. However, local arrangements may differ, and it is advisable to contact the local laboratory to determine whether a result will be available within this time.
• CKS recommends seeking specialist advice regarding the management of non-immune pregnant women who have been in contact with chickenpox, in view of the potential for the development of severe disease and serious complications for the woman and fetus and the possible need for varicella-zoster immunoglobulin.
• CKS found no published controlled trials of the use of prophylactic oral aciclovir in pregnancy. Aciclovir, valaciclovir, and famciclovir are not licensed in the UK for this indication and are generally not recommended [DTB, 2005a; HPA, 2007a].
• The local microbiologist or virologist will usually decide whether to give varicella-zoster immunoglobulin [DTB, 2005a].
• The Department of Health recommend that a pregnant woman who has a negative antibody status (or for whom results cannot be available within 10 days of exposure) should receive varicella-zoster immunoglobulin within 10 days of exposure [DH, 2006].