Transition of cytomegalovirus seropositivity in Japanese puerperal women

To investigate the latest serological tendency of cytomegalovirus (CMV) in Japanese puerperal women and to estimate the sequential influence on child-bearing women in Japan.

We studied 3966 puerperal women registered at a cord blood bank. Serum samples were obtained from umbilical cords at delivery and on the third day after delivery. CMV immunoglobulin G (IgG) and CMV immunoglobulin M (IgM) antibodies were determined using enzyme immunoassay kits. Scatter diagrams between seroprevalences and perinatal details were generated, and Pearson product-moment correlation coefficients (r) and coefficients of determination (R(2)) were calculated.

The overall CMV seroprevalence was 68.4% for the IgG antibody and 3.9% for the IgM antibody. IgM seroconversion had occurred separately in 0.28% of the cases without IgG seroconversion. Including outliers on scatter plots, linear decreasing trends were observed for IgG seropositivity with measurement year (r = -0.72, P < 0.05, R(2) = 51.8%) and maternal birth year (r = -0.43, P < 0.05, R(2) = 18.2%). There was a linear increasing tendency for IgG seroprevalence with maternal age (r = 0.46, P < 0.05, R(2) = 21.4%). Without the outlier, a linear decreasing tendency was found for IgM seropositivity (r = -0.85, P < 0.01, R(2) = 71.6%).

CMV seropositivity decreased with maternal youth in Japanese puerperal women. A possible contradiction was identified: decreasing tendencies in the seroprevalence of both IgG and IgM might coexist. We assume that actual CMV infections spread in a transient epidemic manner in which it may not be possible to observe a linear tendency and/or that the actual risk of maternal CMV infection might be decreasing.