What is fifth disease and can I pass it on to my unborn baby?

My son's day care has called and said there has been an outbreak of fifth. I'm 5 months along and need to know if this can give my baby any problems.

Despite the best intentions, pregnant women get sick. Having young children at home can make it almost impossible to avoid catching a bug. Most infections rarely have any effect on pregnancy; however, some can be serious. Fifth disease is one of these. Besides affecting the mother, this infection can cause serious illness in the newborn. But thankfully that's rare. So take a deep breath and read on.

Six childhood illnesses present with a skin rash. The first four are scarlet fever, measles, rubella or German measles, and roseola. Next came Erythema infectiosum commonly known as fifth disease or 'slapped-cheek' because of the fiery red rash that erupts on the cheeks. Fifth disease is caused by parvovirus B19. It's a common infection, and by age 15 about 50 percent of children have had it. Infection also occurs later in life so that by old age over 90 percent of people are immune.

Fifth disease can be mild or serious depending on one's health and immune status. In healthy children, infection is usually mild and brief, often causing no symptoms at all. The rash can wax and wane over a few weeks time and may reappear after exercise. In adults, especially women, about half of those infected experience joint pain and stiffness as with arthritis. Fifth disease can be even more serious for someone with a weakened immune system (from medication or illness) or a blood disorder such as sickle cell anemia.

Outbreaks of fifth disease are more common in late winter, spring and early summer. The virus lives in respiratory secretions in the nose and throat and is spread by close contact. But not everyone who is exposed to the virus gets infected. In school outbreaks less than 50 percent of children become infected. Among family members or household contacts, the odds of acquiring the illness are about 50-50.

Infection can also be transmitted by blood or blood products, or across the placenta during pregnancy. If a pregnant woman develops fifth disease, she runs a one in three chance of passing the infection to her baby. In a study of 618 pregnant women who were exposed to the virus, only half of the women were susceptible to infection and only 52 women became infected (Harger, J. Prospective evaluation of 618 pregnant women exposed to parvovirus B19: Risks and symptoms. Obstet. Gynecol. 1998;91:413-420).

How the virus affects pregnancy depends largely on the timing of infection. When infection occurs in the first trimester miscarriage is common. Birth defects can also occur. In the second trimester the immune system is still immature and infections can be serious. In rare cases (3 percent) it leads to heart failure and a condition known as hydrops fetalis or stillbirth. Infections in the third trimester can be easier on the fetus because their immune response is more developed. Women who get this infection during pregnancy are followed closely with frequent ultrasounds to keep an eye on the developing baby.

The odds are in your favor, but it's important to be on the safe side and check things out. If you think you've been exposed to fifth disease, get a blood test to measure your antibody levels and see if you're immune. Only women who have never had the infection, and have no immunity, can pass the infection on to their baby. While infection during pregnancy can lead to problems, in most cases it does not. -- June 5, 2001

Wishing you health,

Labels: Pregnancy health