Chicken-pox and shingles in Pregnancy
What should I do if I am exposed to chicken-pox during pregnancy?
You need to have your immunity checked. You will probably know whether you have had chicken-pox earlier in life. If that is the case, then you are in the clear. Ninety per cent 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.
If, on checking immunity, one is found to be susceptible, what then?
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 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.
What effects do chicken pox infected fetuses suffer from?
It could be a few or more of these:
large patches of skin scarring
eye complications, including cataracts and scarring inside the eye
deformed, even absent fingers and/or toes
It is important to remember that only a small proportion of babies 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.
Why is delivery during active chicken-pox infection uniquely significant?
Babies born in such a situation are susceptible to develop a severe and generalized infection in less than a week post-delivery.
Up to a third of babies are affected. This is because the baby has not had time to acquire protective antibodies normally passed to him or her from the mother across the placenta.
To try to prevent or at least moderate the effects, paediatric specialists will evaluate the situation and will put in place management measures, which may include a combination of vaccination, passive immunization and antiviral medication.
Is there anything that can be done if a pregnant woman develops chicken-pox in pregnancy?
If the infection has already developed, nothing can be done.
What if the woman is seen immediately after exposure, before the infection?
The incubation period of chicken-pox is ten to twenty days. If the investigations to establish the immune status are carried out promptly, there is enough time to intervene before the manifestation of the infection. Passive immunity in the form of injection might be considered. This is meant to moderate the effects of the infection in the mother (and therefore the baby). It rarely prevents it altogether.
There is really no consensus on the necessity of this and some experts argue that if the infection exposure is beyond the first twelve to fourteen weeks of gestation, the risk to the baby is very small anyway and passive immunity is unnecessary. An exception to this is those mothers who, for some reason, have low immunity in general.
Can one be vaccinated against chicken-pox if exposed to it during pregnancy?
Chicken-pox vaccine cannot be administered during pregnancy. The vaccine uses an attenuated (weakened) virus. It is therefore contra-indicated for use in pregnancy.
What is the relationship between chicken-pox and shingles?
Shingles can be described as a later manifestation of chickenpox. The two are really one and the same thing.
The virus that causes chicken-pox usually stays in the body life-long. This means that even though the individual has life-long immunity against chicken-pox, he or she is still susceptible to developing shingles, which is in fact a reactivation of the same virus. Shingles is usually provoked by a fall in general body immunity.
Shingles is also known by the name herpes zoster or simply as "zoster". This is because the virus which causes chickenpox and shingles is called Varicella zoster, which belongs to the herpes family.
What are the consequences of developing shingles in pregnancy?
The fetus is not at risk. Any mother who develops shingles in pregnancy would have had chicken-pox in the past. This means she is carrying protective antibodies in her circulation, and these are continually passed to the growing fetus, which is thus protected.
Is there any medication that can be used in the event of chicken-pox or shingles in pregnancy?
Normally only symptomatic relief is aimed for in chickenpox, because this is a self-limiting condition. However, if there is any hint of an abnormally severe disease - such as lung involvement - antiviral medication can be used. The standard drug acyclovir has been used in thousands of cases all over the world without any report of untoward effect to mother or baby. However, its absolute safety cannot be guaranteed and it should only be used where the benefits outweigh potential untoward effects.
Can chicken-pox infection cause miscarriage or preterm labour?
Yes. This is uncommon but, if severe, this infection can provoke uterine activity, which may subsequently end in miscarriage or preterm labour, depending on the gestation.