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Column originally published Sep 26, 2006

Human Parvovirus Infection Can Cause Miscarriage

Question: Last year, I had a miscarriage that devastated me. I was about 7- to 8-weeks pregnant at the time. The pregnancy was going wonderfully until I started developing some achy pain in my hands. Around the same time, our three-year-old daughter developed a red rash on her face. We consulted our family doctor at the time, and we were told that she had the ‘slapped-cheek’ disease. Within a short time after that, I had the miscarriage. Several women in our community who were pregnant at the same time also had the same fate. I asked my doctor whether the miscarriage was related to our daughter’s illness, and his answer was no. However, I found on the internet that my daughter’s condition was caused by a parvovirus, which can infect pregnant women. I want to know whether this could have happened to me. I also wonder whether it was possible to prevent this infection if I have had a blood test to check for immunity to this virus.


You have a very interesting and important question here. The short answer to your question is yes, your pregnancy could have been terminated by a parvovirus infection. However, I don’t think you could have prevented this from happening, even if you had a blood test showing that you were susceptible to the virus. Please read on carefully to understand this condition better.

The full name of the virus is Human Parvovirus B19 (HPB19). As the name implies, there are many parvoviruses, but this is the only one that infects humans. It was first discovered in 1975.

HPB19 infection is found all over the world. When scientists looked for evidence of this virus in different communities, they found that only about 10% of children have been infected. This compared with around 50% of adults and more than 90% of elderly people have evidence of previous HPB19 infection. This means that most of us will get infected by the virus some time in our life; the longer we live, the greater is the chance of infection.

HPB19 infection can happen sporadically, but it can also come in epidemics, especially in late winter and early spring. It is believed to spread from person to person through respiratory secretions. Outbreaks of HPB19 infection have occurred in daycares, schools, as well as among family members.

Most of the time, HPB19 infection is asymptomatic, which means those infected may not notice that they are sick, or the symptoms are too mild to be recognized. Once infected, the virus multiplies in a special type of cells in the bone marrow that is called red blood cell precursors: these cells are destined to produce new red blood cells for the body.

In some young children, HPB19 can cause erythema infectiosum or ‘slapped-cheek’ disease. It usually starts with a low grade fever, mild lethargy, sore throat, followed by a red rash on the cheeks. This rash can be very bright, giving the appearance that someone might have slapped the child. A few days later, a lace-like rash can appear on the body and extremities. This lace-like rash tends to come and go, depending on whether the child is exposed to heat and the sun. It may last for as long as several months.

Most adults do not develop this kind of rash. Women tend to experience pain in their joints (this is called arthralgia), although sometimes true arthritis can happen. Those who have a medical condition that causes red blood cells to break down easily (like those with sickle cell disease or spherocytosis) can develop severe anemia for a short time, which may require blood transfusions to tie them over, until their bone marrow recovers, and starts to produce new red blood cells again.

For those individuals who have an immune disease problem, HPB19 infection can lead to prolonged anemia because they cannot fight off the infection, and the virus continues to multiply in their body.

When pregnant women get infected with HPB19, the virus can pass from the mother to the foetus through the placenta. If the infection occurs in early pregnancy, it can stop the bone marrow’s ability to produce red blood cells. As a result, the foetus can develop severe swelling of the body, a condition that is called hydrops. Sometimes a blood transfusion through the umbilical blood vessels before the baby is born can help, although this is a very risky procedure.

Unfortunately, 2% to 6% of foetus infected by this virus during the first half of pregnancy can die, resulting in what is known as miscarriage. Fortunately, most babies infected by HPB19 during their mothers’ pregnancy have no sign of being harmed by the virus at all.

From your description, it is certainly possible that the HPB19 virus infected your daughter as well as others in your community, including yourself and some other pregnant women. As I have mentioned earlier, it is very difficult to stop the spread of this virus. Good hand washing and careful disposal of used facial tissues are recommended, although we don’t know how effective these measures are in preventing the spread of this virus within the family.

Some have advocated that pregnant women should be tested to see whether they have immunity against HPB19 virus. Although this appears to be quite reasonable, the trouble is what should we do with this information. If the woman has immunity, which means that she was infected by this virus before, and she will not be infected again.

However, if the woman does not have immunity, we cannot protect her from HPB19 infection. At the present time, scientists have not been able to produce an effective vaccine against the virus. None of the anti-viral medications are effective against HPB19. If the woman works in a daycare or school, staying away from their job does not prevent infection either. She can still pick up the virus from her other children, or from adults who have been infected and show no sign of infection.

Until an effective vaccine or medication becomes available, testing pregnant women routinely for HPB19 immunity can lead to more anxiety instead of helping them.