Prevalence of congenital cytomegalovirus infection according to the type of maternal infection in Japan.

INTRODUCTION

Variable rates of cytomegalovirus (CMV) seropositivity in mothers from different individual's background may translate to distinct epidemiological patterns of congenital CMV infection.

METHODS

The prospective cohort study was conducted in Japan to evaluate the prevalence of vertical transmission rate according to the type of maternal infection. Post hoc power as a follow-up analysis was evaluated to compare the statistical power with other studies from France, Finland and Brazil. One thousand one hundred sixty-three pregnant women were measured IgG, IgM and IgG avidity index. The urine samples of neonates of these women were evaluated using polymerase chain reaction to diagnose the vertical transmission.

RESULTS

The prevalence of congenital CMV infection in the study population was 0.4%. The proportions of patients with primary and nonprimary infections were 60% and 40%, respectively, with a maternal seroprevalence of 82.5%. The rate of vertical transmission among the seronegative pregnant women before pregnancy was statistically higher than that among the seropositive pregnant women before pregnancy (p < 0.05), with a study power of 52.7%. The same difference was observed in France and Finland for maternal seroprevalence of 61% and 72% and statistical power of 56.9% and 66.7%, respectively.

CONCLUSION

The maternal seroprevalence of the present study conducted in Japan was much higher than that of studies in France and Finland. Nevertheless, seronegative pregnant women had a higher risk of vertical transmission before pregnancy.