Fifth disease is a childhood illness that can pose risks to the fetus if a mother contracts it during pregnancy.
About 50 percent of pregnant women are immune to fifth disease because they had the illness in the past (1). (There is no vaccine against this infection.) Women who are immune to fifth disease cannot become infected and do not need to be concerned about it during pregnancy. However, most women do not know whether they had this illness in the past. Pregnant women should discuss this illness with their health care provider during their first prenatal visit.
What is fifth disease?
Fifth disease (erythema infectiosum) is a common, usually mild illness spread through the air from an infected person's cough or sneeze. In children, it causes a distinctive “slapped cheek” rash and, less commonly, a low-grade fever, headache, sore throat and joint pain. Infected adults are less likely to develop a rash, but often experience joint pain and swelling, sometimes with mild flu-like symptoms. Symptoms generally appear between 4 and 14 days after exposure.
Fifth disease is caused by parvovirus B19. It got its name many years ago when it appeared fifth in a list of what were considered the common causes of childhood rash and fever.
Many infected people have no symptoms. About 50 percent of adults have had the infection in childhood, often without knowing it (2).
How is fifth disease diagnosed?
When the rash is present, fifth disease can be diagnosed by a physical examination. If there is no rash, blood tests can help diagnose the illness (3).
What risk does parvovirus B19 infection pose to the fetus?
Fetal infection is rare. However, when a fetus does become infected, the virus can disrupt its ability to produce red blood cells, sometimes leading to a dangerous form of anemia that can result in heart failure. Up to 6 percent of infected fetuses die (3). Fetal deaths are more likely when a pregnant woman contracts the infection in the first 20 weeks of pregnancy (1).
Fifth disease in pregnancy has not been proven to cause other birth defects (2).
How common is fifth disease in pregnancy?
About 1 in 400 women in the
Who is at risk of fifth disease?
Any susceptible person can catch it. It's best for a pregnant woman to assume that she is susceptible. Women at highest risk of exposure are mothers with young children and those who work as teachers and childcare providers.
To reduce the risk of infection, pregnant women should wash their hands thoroughly after touching tissues used by infected children and dispose of these tissues promptly. They also should avoid sharing drinking glasses or utensils with anyone who has or was exposed to the illness. A blood test can determine susceptibility.
What should a pregnant woman do if she has been exposed to fifth disease?
A pregnant woman who has been exposed to fifth disease should consult her provider promptly. If she was exposed to an infected person during the contagious stage of the illness (generally before the rash develops), her provider may recommend a blood test to determine whether she has had fifth disease in the past and is immune, or if she currently has it.
How is fifth disease in a pregnant woman treated?
There is no drug to treat fifth disease. If a pregnant woman becomes infected, her provider monitors the pregnancy carefully for signs of fetal problems. The provider will most likely recommend repeated ultrasound examinations (weekly or every other week) for 8-12 weeks after the mother was infected (4). If ultrasound does not show any problems during this time, no further testing is recommended.
Researchers are seeking the most effective way to treat fetuses affected by severe anemia and other complications of fifth disease. If ultrasound suggests that the fetus is developing complications, the provider may recommend amniocentesis (inserting a thin needle into the uterus and withdrawing a small sample of amniotic fluid) to confirm the infection.
In some cases, the provider also may recommend a procedure called cordocentesis (a thin needle is inserted into a vein in the umbilical cord to take a small sample of fetal blood) to help determine the severity of fetal anemia. The inserted needle also can be used to deliver a blood transfusion directly into an umbilical vein. It is not yet known how effective this treatment is, although some studies suggest that up to 80 percent of severely ill fetuses survive after an intrauterine blood transfusion (4).
Some fetuses with severe complications from parvovirus infection have recovered without treatment and appear normal at birth (4).
For more information
Read the fact sheet provided by the Organization of Teratology Information Specialists (OTIS).
- Centers for Disease Control and Prevention (CDC). Parvovirus B19 Infection and Pregnancy.
- Servey, J.T. Clinical Presentations of Parvovirus B19 Infection. American Family Physician, volume 75, number 3,
- Ramirez, M.M., and Mastrobattista, J.M. Diagnosis and Management of Human Parvovirus B19 Infection. Clinics in Perinatology, 2005, pages 697-704.
April 2007
