Perinatologist Corner - C.E.U/C.M.E. Modules
Varicella in Pregnancy
3. Background
Case scenario #1
WG is a 26 y/o G2P1 at 16 weeks gestation who works as a day-care attendant.
She reports that one of the children in her group was sent home because of
chicken pox. She remembers that her mother always told her that she herself
never had chicken pox as a child. Should she be concerned that this could pose
any risk to her developing fetus?
Background
In the United States over 95% of women are immune to varicella. (Chapman)
The incidence of varicella in pregnancy is about 1 in 2000, so if you know the
annual number of births at your service unit, you can get an idea of about how
often you will be confronted with the situation. A person is contagious for 1 to 2
days before the onset of the skin lesions until all the lesions are crusted, usually
about 4 to 7 days after the vesicles appear. The incubation period is 10 to 21
days. The transmission is person to person and results from contact with both
vesicular fluid and respiratory secretions. The attack rate is a very efficient 90 %
for persons in close direct contact. These significant exposures include
household contacts, close indoors contacts over 1 hour, hospital roommate, or
prolonged face to face contact. The good news is that 80 to 90% of women with
no prior history of varicella have immunologic evidence of past infection. (Hollier)
The diagnosis is usually made clinically based on the history and type of
eruption. The easiest laboratory test to perform, and also the most sensitive (86
to 97%), is the ELISA which tests for IgG antibodies to the virus and indicates
immunity from a remote exposure. (Maupin)