Longitudinal evaluation of parvovirus B19 infection among pregnant women at Ribeirão Preto, SP, Brazil - Revista Brasileira de Ginecologia e Obstetrícia

PURPOSE: to evaluate the rate of seropositivity for parvovirus B19 (PB19) among pregnant women and the rate of seroconversion against this infection during pregnancy. METHODS: prospective study carried out in the Hospital of the Medical School of Ribeirão Preto, University of São Paulo. In the first stage of the present study, we evaluated 245 pregnant women with gestational age less than 16 weeks to determine the seroprevalence of PB19 infection by ELISA. According to the serological results we determined if the PB19 infection was an acute infection (IgM positive and IgG negative or positive), or a former infection (IgM negative and IgG positive). In the second stage of this study, 73 previously seronegative pregnant women were tested again when they came to the hospital for delivery (IgM and IgG), to detect the seroconversion rate during pregnancy. RESULTS: the seroprevalence of the PB19 infection until 16 weeks of gestation was 62.9% (95% IC: 56.8-68.9), divided into acute infection (8.1%), or former infection (54.8%). Of the 73 patients, seronegative in the first stage of this investigation, seven (9.6%) showed seroconversion during pregnancy (95% IC: 2.8-16.3), two (2.7%) showed acute serological infection and five (6.9%) presented markers of past infection. The final seroprevalence of PB19 infection during pregnancy was 72.5%. CONCLUSIONS: considering that only the acute PB19 infection is associated with risk for vertical transmission, the high seroprevalence of this infection observed in this study would be protecting these fetuses against this form of infection. Despite the relatively high rate of seroconversion against PB19 infection during the pregnancy period, we did not observe any symptomatic neonate in this group.