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:
- presence of fetal ascites
- development of generalised hydrops fetalis
- fetal hepatomegaly
- increased (> 95th centile) cardiac biventricular outer diameter
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
Treatment and prognosis
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:
- 1. Riipinen A, Väisänen E, Nuutila M et-al. Parvovirus b19 infection in fetal deaths. Clin. Infect. Dis. 2008;47 (12): 1519-25. doi:10.1086/593190 - Pubmed citation
- 2. Schild RL, Bald R, Plath H et-al. Intrauterine management of fetal parvovirus B19 infection. Ultrasound Obstet Gynecol. 1999;13 (3): 161-6. doi:10.1046/j.1469-0705.1999.13030161.x - Pubmed citation
- 3. Simms RA, Liebling RE, Patel RR et-al. Management and outcome of pregnancies with parvovirus B19 infection over seven years in a tertiary fetal medicine unit. Fetal. Diagn. Ther. 2009;25 (4): 373-8. doi:10.1159/000236149 - Pubmed citation
- 4. Katz VL, Mccoy MC, Kuller JA et-al. An association between fetal parvovirus B19 infection and fetal anomalies: a report of two cases. Am J Perinatol. 1996;13 (1): 43-5. doi:10.1055/s-2007-994201 - Pubmed citation
- 5. Merz E, Bahlmann F. Ultrasound in obstetrics and gynecology. Thieme Medical Publishers. (2005) ISBN:1588901475. Read it at Google Books - Find it at Amazon
- 6. Ergaz Z, Ornoy A. Parvovirus B19 in pregnancy. Reprod. Toxicol. 2006;21 (4): 421-35. doi:10.1016/j.reprotox.2005.01.006 - Pubmed citation
- 7. Prayer D. Fetal MRI. Springer Verlag. (2010) ISBN:3540732705. Read it at Google Books - Find it at Amazon
- 7. Tolfvenstam T, Broliden K. Parvovirus B19 infection. Semin Fetal Neonatal Med. 2009;14 (4): 218-21. doi:10.1016/j.siny.2009.01.007 - Pubmed citation
- 8. De jong EP, De haan TR, Kroes AC et-al. Parvovirus B19 infection in pregnancy. J. Clin. Virol. 2006;36 (1): 1-7. doi:10.1016/j.jcv.2006.01.004 - Pubmed citation
- 9. Eis-hübinger AM, Dieck D, Schild R et-al. Parvovirus B19 infection in pregnancy. Intervirology. 1998;41 (4-5): 178-84. Intervirology (link) - Pubmed citation
- 10. Von kaisenberg CS, Jonat W. Fetal parvovirus B19 infection. Ultrasound Obstet Gynecol. 2001;18 (3): 280-8. doi:10.1046/j.1469-0705.2001.00471.x - Pubmed citation