Varicella Immunity Testing Prior to Pregnancy

Prior to attempting pregnancy through infertility treatment, fertility specialists recommend varicella immunity testing. Mothers who are not immune to the virus are at risk of contracting the illness, which has been linked to the possibility of birth defects.

What is varicella?

Varicella is a viral infection that is part of the herpes family. Also known as varicella zoster virus, the most common condition caused by varicella is chickenpox. Approximately 90 percent of women are immune to chickenpox because they have been vaccinated or they had the virus in the past.

The primary symptoms of active chickenpox are an itchy rash, fever and outbreak of fluid-filled blisters. The virus is highly contagious during the active phase and easily spreads when someone with an active varicella infection coughs or sneezes or when another person comes into contact with the fluid inside the blister.

Varicella health risks to fetus

The health risks of varicella during pregnancy depend on the stage of pregnancy when the infection occurs. During the first 20 weeks of pregnancy, a small percentage – 1 to 2 percent – of fetuses develop a condition called congenital varicella syndrome, which can lead to the following birth defects:

• Extremity (arms and legs) development issues
• Scarring
• Microcephaly (abnormally small head)
• Abnormal brain development
• Eye inflammation that can lead to blindness

When varicella is contracted later in pregnancy, the fetus is much less likely to suffer from complications, unless the varicella rash occurs close to the delivery date. Women that have chickenpox within three weeks of delivering have a risk of passing the virus to their babies. When the rash appears in the days immediately before or after delivery, the baby is at risk of developing a serious varicella infection that can even be life-threatening.

Testing varicella immunity prior to pregnancy

Because of the fetal health risks associated with chickenpox, it is important a woman’s varicella immunity be tested prior to attempting pregnancy through infertility treatment.Immunity is determined through a Varicella IgG Antibody Titer, a blood test that measures the antibody level produced by the immune system in response to the varicella virus.

The American Society for Reproductive Medicine recommends all adults without documented proof of varicella immunity receive two doses of varicella vaccine or a single dose if only one was previously administered. In cases where a woman is exposed to the varicella virus, the vaccine should be administered within 96 hours of exposure and pregnancy attempts delayed for a month.

Since the vaccine is a live attenuated virus, it should not be administered during pregnancy.Fertility specialists recommend the vaccine be given a minimum of one month prior to pregnancy.