Cytomegalovirus seroprevalence among pregnant women in Nagasaki, Japan.

BACKGROUND

Cytomegalovirus (CMV) infection in pregnant women can result in congenital disease. Since the transplacental transmission rate is considerably higher in primary maternal infections than in non-primary infections, understanding CMV seroprevalence among pregnant women is crucial for increasing the implementation of preventive healthcare.

METHODS

A population-based cross-sectional cohort study was conducted between 2014 and 2017 in Nagasaki City (the capital) and in Goto City, a remote island in Nagasaki Prefecture. We collected blood samples from pregnant women around 12 gestational weeks, and measured CMV-specific IgG antibodies using an enzyme immunoassay. We also investigated maternal age, gestational age, and the number of previous births at the time of blood sampling.

RESULTS

We analyzed 8901 subjects (8388 cases in Nagasaki City and 513 cases in Goto City). The CMV seropositive rate was 78.2% in Nagasaki City, which had declined by 9% over 13 years, and 81.3% in Goto City, with no significant difference between the two regions (p = 0.0951). A multivariate logistic regression analysis revealed significant correlations between the CMV seropositive rate and maternal age (odds ratio 1.012 [p = 0.0172, 95% CI: 1.002-1.023]) or the number of previous births (odds ratio 1.363 [p < 0.0001, 95% CI: 1.279-1.454]).

CONCLUSIONS

A much higher risk of intrauterine CMV infection following maternal primary infection, a trend of decreasing CMV seropositivity, and an apparent risk of CMV infection during child-rearing indicate the necessity of preventive measures during the preconception period and during pregnancy.