Serological and virological analysis of maternal and fetal blood samples in prenatal human parvovirus b19 infection.

BACKGROUND

Intrauterine parvovirus B19 (B19V) infection can be asymptomatic or may cause severe fetal complications. Information on serological and virological findings of infection in the fetus is scarce.

METHODS

We determined B19V-DNA and anti-B19V antibodies in maternal and fetal blood samples obtained from 41 pregnancies that were complicated by prenatal B19V infection. Most fetuses presented with moderate to severe anemia or hydrops.

RESULTS

At the time of fetal blood sampling, all mothers were B19V-DNA positive and B19V-IgG positive. B19V-IgM was detected in 95% of maternal blood samples. B19V-DNA, B19V-IgM, and B19V-IgG were detected in 100%, 28%, and 24% of fetal blood samples, respectively. The probability of a positive B19V-IgG or B19V-IgM finding in fetal blood increased with gestational age. B19V-IgG levels in maternal blood did not correlate with the likelihood of a positive B19V-IgG test in the fetus. The presence of B19V-IgG in fetal blood was accompanied by lower B19V-DNA levels and less severe clinical findings.

CONCLUSIONS

The lack of B19V-IgG in fetuses with B19V-derived anemia or hydrops is most likely due to a limited materno-fetal transfer of IgG and a poor fetal antibody response. Fetal B19V infection is poorly controlled in the absence of specific antibodies.