Childhood viruses can cause problems

You're in your second month of pregnancy and a friend you saw yesterday calls. She tells you she's sick as a dog with what she thinks is the flu. Should you worry? Not if it is flu (though you may be in for a few unpleasant days). But other respiratory viruses and childhood diseases can cause serious problems for your growing baby if you develop them while you're pregnant.

Influenza hardly ever causes birth defects, though you should get a flu shot at the start of flu season to protect yourself. If you are exposed to chickenpox, fifth disease, cytomegalovirus (CMV) or rubella while you are pregnant, however, tell your doctor immediately. Here are some things you should know about these viruses and their effect on your pregnancy.

Chickenpox: A serious problem for a few women

This is a highly contagious disease that can cause birth defects. If you had chickenpox in the past or are vaccinated against chicken pox, then you cannot get it again and your baby will be fine. If you aren't sure if you had chickenpox, call the doctor for a blood test to see if you are immune. The March of Dimes estimates that between 85 and 95 percent of pregnant women are immune to chickenpox. Those who are not immune should not receive the chickenpox vaccine during pregnancy. About 7 women in 10,000 will have chickenpox during pregnancy.

If you are pregnant and have been exposed to chickenpox, your doctor may prescribe a medication called VZIG, which is safe for both you and your baby. When this drug is given within 96 hours of exposure it helps prevent chickenpox or reduces its severity. One complication of chickenpox is pneumonia, which you do not want to have while pregnant. Doctors don't know yet whether VZIG will help protect the fetus from the infection.

Fifth disease can harm the fetus

Fifth disease is a common childhood disease that causes a distinctive "slapped cheek" rash, mild fever, headache and sore throat in children. About 50 percent of pregnant women are immune to it and don't have to worry about exposure. Most fetuses are not affected when their mothers get this virus.

However, when the fetus does become infected, fifth disease can cause anemia, heart failure, miscarriage or stillbirth. There is no vaccine or treatment for the disease. If you contract it, your doctor will monitor your pregnancy carefully with repeated ultrasounds.

Prevention is key to Cytomegalovirus

This virus affects 1 of every 100 pregnant women and it can cause birth defects. Women who work in day care centers and health care workers have the highest risk of infection. The best means of prevention is constant hand-washing and avoiding contact with babies' mouths and faces when cuddling. It's a stealthy virus because the first infection with CMV may cause no symptoms. An active infection, however, may produce prolonged high fever, chills, severe tiredness, an overall ill feeling, headache, or an enlarged spleen. There is also no treatment. If you think you have been exposed, call the doctor immediately.

Rubella: Once feared, now rare

Once the scourge of pregnant women, this harmful virus that causes birth defects is now rare. Since 1969 almost all children have been vaccinated against rubella (also known as German measles), so pregnant women and their babies are much safer. If you are exposed to rubella when you are pregnant, however, you can have blood tests and be sure you are immune. Your baby should be vaccinated against rubella at between 12 and 15 months, usually in combination with measles and mumps vaccines. This combined vaccination is called the MMR. A second dose is given between the ages of 4 and 6 years. If you are not immune, you may receive the MMR or rubella vaccine soon after birth.

Date last reviewed: October 2002.

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