Medical Q&As

Chicken pox - risk to foetus?

My fiancée is 35 weeks pregnant and has had chicken pox, but has been in contact with a child who is now infected. What is the risk to our unborn child? Can the foetus become infected or worse?

Since your fiancée has already had chicken pox she has antibodies to the virus, which renders her immune from further infection. Such immunity is life long so she will never acquire chicken pox again and more particularly she does not need to worry about her unborn child being in any way at risk. In other words once she has already had chicken pox there is no risk to the baby or to her. Most women have antibodies to chicken pox virus even though many of them may have no recollection of ever having had the infection. It is possible to have a silent infection, which means that the virus has infected the body but the person does not manifest symptoms. This accounts for the fact that 80% of the adult female population have chicken pox antibodies but far fewer that that recall actually having the illness. Even in situations where an expectant mother does not have antibodies it is extremely uncommon for any harm to occur to the foetus should the mother become infected during pregnancy. However, if a mother were to develop chicken pox during pregnancy the infection is often more severe than it would be were she not pregnant. In summary, your fiancée has no need to worry.