Chickenpox Exposure in Pregnancy

Question 1

If a woman has exposure to chickenpox during pregnancy what should you do?

Answer 1

1. If previous history then no action needed.
2. If there is any doubt or no past history of the mother previously having chickenpox, maternal blood should be checked for varicella antibodies (VZV IgG). Do this on same day.
   
   • ​​If present, no action needed.
   • If not present - Give VZVIG.
     
     • ​Advise she is infectious for 8-28 days after contact.
     • Discuss option of post partum vaccination

Question 2

What is defined as significant exposure with regards to chickenpox and pregnancy?

Answer 2

• Face to face contact
• 15 minutes or more of being in the same room.
• Contact in the setting of a large open ward

Question 3

If a woman develops chickenpox (even if had VZVIG) what should you do?

Answer 3

• Tell her to avoid contact with susceptible individuals.
• Give aciclovir to all women if within 24 hours of developing the rash. (5 times a day for 7 days)

Question 4

If she develops a severe infection, what should be done?

Answer 4

She will need to be referred to hospital and have IV aciclovir.

Question 5

If she is <28 weeks gestation, what should be done?

Answer 5

• Still give aciclovir.
• Tell her there is a small risk of FVS (Fetal Varicella Syndrome) ~1%
• Refer to fetal medicine specialist at 16-20 weeks or 5 weeks after infection.

Question 6

A 25 year old lady who is 18 weeks pregnant presents to your surgery after coming in contact with a friend’s child who has symptoms of chicken pox. This is the second time this has happened, previously this occurred 29 days ago and you arranged VZIG (varicella zoster immune globulin) administration as she was not immune. What would be the correct management for her now?

Answer 6

If a non-immune pregnant patient is exposed to chicken pox she sould be offered VZIG as soon as possible. VZIG is effective when given up to 10 days after contact (in the case of continuous exposures, this is defined as 10 days from the appearance of the rash in the index case).

A second dose of VZIG may be required i_f a further exposure is reported_ _and 3 weeks (21 days) have elapsed since the last dose_.

Question 7

How many days after exposure to chicken pox is VZV Ig effective?

Answer 7

Up to 10 days post exposure.

Question 8

When does FVS usually occur?

Answer 8

It usually occurs before 20 weeks but can occur up to 28 weeks.

No cases documented after 28 weeks.

Question 9

What are the features of FVS?

Answer 9

• Skin scarring
• eye defects (microphthalmia)
• Limb hypoplasia
• Microencephaly
• Learning disabilities

Question 10

What is neonatal varicella and what is the risk to the child?

Answer 10

If the mother gets chickenpox/shingles 5 days before and 2 days after birth then there is a risk of neonatal varicella.

20% of cases of neonatal varicella result in death.