RCOG | Chickenpox in pregnancy

This is a new guideline from RCOG on managing chickenpox in pregnancy. It doesn't change our management, but I'm doing a quick summary as I often forget what is classed as significant contact and when immunoglobulin is advised.

Why is it important? 

Fetal Varicella Syndrome (FVS) can occur if a woman has chickenpox during pregnancy. It's been seen with infections as early as 3/40 and as late as 28/40.

How do we identify those at risk?

Women should be asked at booking whether they've had chickenpox. If they've not, they should be advised to attend the GP if they have contact with it.
People from a subtropical country are much less likely to have had it, so you should assume that they haven't, rather than just relying on history.

How do we manage a pregnant woman who's had contact with chickenpox or shingles? 

  • Ask if they've had it previously. If so, no further action is required.
  • If they've not had it, or there is an uncertain history, or they are from a subtropical country, then check VZVIgG ( varicella zoster virus immunoglobulin G - this can be done off the booking bloods if the lab still has them).
  • If VZVIgG is positive, no further action is required - the woman can be reassured she has immunity.
  • If VZVIgG is negative, then see if the exposure was significant (see below). If it was, then give VZIG (varicella sister immunoglobulin) as soon as possible within 10d. If the exposure has been continuous, give it within 10d of the rash appearing in the index case.
  • Advice the woman to contact the GP immediately if she develops a rash (as aciclovir needs starting within 24 hrs).

What if there is recurrent exposure?

If it is more than 3 weeks since the last dose of VZIG, she should be given a further dose.

What constitutes significant exposure?

Contract with chickenpoxif2d before the rash appears until it has crusted over (normally5d).

Contact with shingles if:

  • it is disseminated
  • it is in an exposed area (it is only very rarely infective in a covered area eg on the back)
  • it is in someone immunocompromised

In both cases the contact is significant if:

  • there is face to face contact
  • contact was for 15 or more mins
  • it was on an open ward setting

What if the woman gets chickenpox?

  • They should have aciclovir if they present within 24 hrs of the rash appearing and are over (20/40). If they are below 20/40, you should consider aciclovir as it is thought to be safe.
  • Advise her to contact the GP if she feels more unwell or if she has respiratory symptoms - it can be much more severe in pregnancy.
  • She needs referring to Obs and Gynae to be seen at around 16-20/40 or 5w after infection if it is later. They may do USS or amniocentesis to look for FVS.

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