How unsafe is the varicella vaccination during pregnancy?

Q: I found out that I was 3 weeks pregnant a week after receiving a varicella vaccination. What are the risks of abnormalities on the fetus and pregnancy due to this? Is terminating the pregnancy recommended?

A:The manufacturers of varicella vaccine and drug control authorities recommend that (a) it should not be given to women who are expecting and (b) non-pregnant women should use contraception for three months after injection. These recommendations are given to avoid malpractice suits in case something goes wrong.Scientifically no studies have been conducted to determine the effect of the vaccine on the unborn baby. Such a trial can not be done because of ethical reasons. Thus we do not really know whether the vaccine has an adverse effect or not.However one case has been reported where a pregnant woman got infected from the vaccine strain of the varicella from her child. As an abundant precaution, pregnancy was terminated. However when the foetus was tested, there was no sign of varicella infection. Thus in retrospect, the termination of pregnancy was not required.In view of the above evidence, from a clinical viewpoint it is not necessary to terminate pregnancy for this reason. As a matter of abundant precaution though serial sonography tests should be done frequently to make sure that the baby is normal. However there can be other considerations to take a different view from family to family.