Chicken-pox is also known as Varicella disease. The classic chicken pox is caused
by the same virus that causes shingles. In fact, shingles is a reactivation of an
old chicken-pox infection. This is because when you have been infected with the chicken
pox virus, it stays in the body for life. That is the case with most people.
If you know that you have been exposed to chicken-pox during pregnancy, you need
to have your immunity checked.
You will probably know whether you have had chicken-pox in the past. If that is the
case, then you are in the clear. 90% of all women of child-bearing age are immune,
by virtue of previous infection, and therefore exposure during pregnancy poses no
risk to their babies. This of course leaves one in ten who are susceptible.
Susceptible women exposed to chicken-pox
If a pregnant woman is exposed to chicken-pox and goes on to acquire the infection,
there is a 14%(1 in 7) risk of pulmonary (lung) involvement. This is a serious complications
and in rare cases can be fatal.
The potential effects on the fetus depend on the gestation.The known effects to the
baby will occur in about 10% of babies if the infection is in the first twelve weeks
of gestation. The so-called fetal varicella syndrome will affect about 1 in 70 of
those affected in the first and second trimesters.
The potential damage is less if the infection occurs later. The exception to this
is if the baby is born within the period when the infection is still active.
Fetal varicella syndrome
Features of the syndrome could be a few or more of these:
· Large patches of skin scarring
· Small head (microcephaly)
· Eye complications, including cataracts and scarring inside the eye
· Paralysis of limbs
· Deformed, even absent fingers and/or toes
It is important to remember that only a small proportion of babies (1.4%) whose mothers
acquired the infection in pregnancy will be affected. It is also true that the later
the infection in pregnancy, the milder the fetal effect.
In some cases, babies are found to have no identifiable effect and may only suffer
shingles later on in infancy or early childhood.