Fetal parvovirus B19 infection

Dr Henry Knipe and Dr Yuranga Weerakkody et al.

Fetal parvovirus B19 infection is a type of in utero infection. In certain cases it can lead to intra-uterine fetal death. 

It was first reported to be associated with fetal death and hydrops fetalis in 1984. Human parvovirus B19 is the only known parovirus virus pathogenic to humans. It is a small single-stranded DNA virus and a potent inhibitor of erythropoiesis, due to its cytotoxicity to erythroid progenitor cells 8. The virus is able to cross the placenta of women infected during pregnancy. Parvovirus B19 may be transmitted from mother to fetus transplacentally in ~ 30% of maternal infections.

Amongst it's many other features, It is notorious for causing a profound fetal anaemia(s) mainly as a result of the parvovirus avidly attacking fetal red blood cells. 

The fetus affected by B19 essentially resembles adults and children with chronic haemolytic anaemias due to decreased erythrocyte production. High output cardiac failure, secondary to anaemia, leads to fluid accumulation and hydrops fetalis. Myocarditis leading to heart failure may also contribute to the development of fetal hydrops.

The risk of maternal to fetal transmission is higher in the 1st and 2nd trimesters. Approximately one-quarter of the women infected during pregnancy may transmit the virus to the fetus.  

  • maternal B19-specific IgG: indicates past infection/immunity
  • maternal B19-specific IgM: indicates recent infection

There can be some overlap in sonographic features which are also common to other fetal infections. Sonographically detectable features include:

The presence of a fetal anaemia can lead to changes in the fetal MCA doppler flow - from high to low resistance.

  • resultant hydrops fetalis (from fetal anaemia and/or involvement of cardiac myocytes): parvovirus infection can cause up to 27% of cases of non immune hydrops fetalis 10

A significant part of management in focused to treating the fetal anaemia, in appropriate cases, cordocentesis followed by intra-uterine transfusion with packed red cells into the umbilical vein can be performed. The development of hydrops fetalis indicates a poorer prognosis.

For sonographic features consider: 

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Article information

rID: 13776
System: Obstetrics
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • In utero parvovirus B19 infection
  • Fetal parvovirus infection
  • In utero parvovirus infection
  • Congenital parvovirus infection
  • Fifth disease
  • Erythema infectiosum

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