Updates

Parvo Virus

Conditions

min. read

Topics

What is the Parvo Virus?

NCBI Parvovirus B19 is a widespread viral infection that often occurs in childhood and may affect persons of all ages and ethnic groups. In August 2024, the Centers for Disease Control and Prevention (CDC) issued a health advisory to health care providers, public health authorities and the public about increases in parvovirus B19 activity in the US. 

This health advisory includes reports from clinicians of clusters with more than the expected number of cases of parvovirus B19 infections among pregnant people in the US, including cases resulting in severe fetal anemia requiring fetal transfusions or pregnancy loss, and increases in aplastic anemia among people with sickle cell disease. 

Historically, 1-5% of pregnant women in the US may be affected by this virus during normal times with most having normal pregnancy outcomes. During epidemics, outbreaks and pandemics, the infection rate is higher: between 3 and 20%. 

Such an increase in parvovirus B19 in pregnant women also is being seen around the world:

  • An Israeli study of 2.7 million anonymized electronic medical records between January 2015 and September 2023 showed an increase each year in pregnant patients almost twice that of the overall patients. There is no longer a seasonal period for the virus to appear. 
  • Northwest Europe has seen a doubling of intrauterine transfusion for parvo year over year across multiple fetal centers; the biggest surge was in May 2024 (last month for which data was published); this also seems to be bucking the seasonal trend. 
  • Denmark saw a large spike in March-April 2024, 3.5 times higher than the last epidemic in 2017. 

Potential Complications of Parvovirus in Pregnant Women

If you have already had a parvovirus B19 infection and you have immune protection, this usually gives you and your baby protection from the virus. Those who are not immune will not necessarily become infected. If you are infected with parvovirus during pregnancy, it is possible the virus will spread to your developing baby. While most of these pregnant women with parvovirus infection have unaffected healthy babies, it is possible for your baby to develop complications such as severe anemia, non-immune fetal hydrops (significant swelling/edema) and intrauterine fetal death.  If you suspect you have been exposed to or have evidence of a parvovirus infection, you should let your health care provider know about your potential risk.

Because infection during pregnancy can cause fetal damage, depending on gestational age at the time of infection, the Texas Children’s Maternal Fetal Medicine Center is bringing attention to the complications that may result from an acute infection and that are cared for in our facilities.

Treating Pregnancies with Parvovirus B19

If an obstetrician suspects this viral infection in a pregnant woman at high risk for exposure, he or she will refer the patient to our Maternal Fetal Medicine Center. Blood will be drawn to assess your antibodies and determine you had a recent infection.  If there is evidence of a recent infection, ultrasound will be performed to assess for potential changes in your baby, such as anemia.  If these changes are detected, treatment options are available, such as transfusion for your baby while in uter

Visit our Maternal Fetal Medicine department for more information or to schedule an appointment.