Erythrovirus B19 during pregnancy

• erythrovirus (formerly parvovirus) type B19 is the cause of 'fifth disease' (also known as slapped cheek disease and erythema infectiosum)
• between 50-60% of adults have been infected previously with parvovirus but the infection has been asymptomatic
• infection with erythrovirus B19 is uncommon in pregnancy
• the majority pregnant women with parvovirus infection have normal, healthy babies
• but there has been fetal death and occasional hydrops fetalis associated with the infection (1)
• there is no routine screening test for parvovirus B19 in pregnancy
• the risk of intrauterine transmission increases with gestational age
  • < 4 weeks - 0%
  • 5-16 weeks - 15%
  • > 16 weeks - 25-70% (2)
• there is a risk of fetal death in about 10% of cases
  • adverse fetal/neonatal outcomes associated with fetal infection include:
    • risk of adverse fetal/neonatal outcomes vary with respect to gestational age at the time of infection with parvovirus:
      • if parvovirus infection occurs in the first 20 weeks of pregnancy, the risk of miscarriage rises from the 5% that a woman who is not infected with the virus has, to 15%
      • if parvovirus infection occurs in weeks 9-20, as well as the 15% risk of a miscarriage, there is also a 3% risk your baby will develop non-immune hydrops fetalis
        • hydrops fetalis is fatal in about 50% of cases
      • other possible of parvovirus infection include growth retardation, myocarditis/infarction, meconium peritonitis, placentomegaly, oedema, anaemia, rashes, thrombocytopaenia, leucopenia and respiratory insufficiency
      • fetal risk is greatest in the second trimester
  • usually these adverse effects tend to occur some 3-5 weeks after the onset of maternal infection (can be later too) (2)
  • if possible parvovirus infection has occurred in pregnency then:
    • check parvovirus serology
    • if positive test in the first 20 weeks of pregnancy, then regular ultrasound scans are indicated to monitor fetal growth and development - if fetal hydrops develops then intrauterine transfusion may be indicated
• there is an approximate 1% risk of congenital abnormality (1)

If considering an infectious cause for the development of the rash in pregnancy. A flowchart summarising contact with vesicular or non-vesicular rash (5):

Open Image in Modal

Reference:

• (1) Health Protection Agency (HPA) 2008. General information on parvovirus: parvovirus B19 (Slapped cheek syndrome, Fifth disease or Erythema infectiosum) – general information
• (2) Morgan-Capner P et al. Guidelines on the management of, and exposure to, rash illness in pregnancy (including consideration of relevant antibody screening programmes in pregnancy). Commun Dis Public Health. 2002;5(1):59-71
• (3) Miller E (1998). Br J Obs Gyn, 105, 174.
• (4) CKS (2007). Pregnancy and parvovirus B19 (‘slapped cheek’ or fifth disease).
• (5) UK Health Security Agency (July 2024). Guidance on the investigation, diagnosis and management of viral illness (plus syphilis), or exposure to viral rash illness, in pregnancy