Maternal cytomegalovirus serology results by geographic region in a large multicenter United States study.

Congenital cytomegalovirus (CMV) infection, due to both nonprimary and primary maternal infection, affects nearly 1% of neonates. In conducting a randomized trial of hyperimmune globulin for prevention of congenital CMV infection, we screened over 200,000 pregnancies across the United States for evidence of prior or primary CMV infection and evaluated their geographic variation. Although the majority were seropositive, seroprevalence and primary infection risk varied significantly by geographic region, with seroprevalence the highest (88%) and primary infection (0.2%) the lowest in the Southwest. This variation in seroprevalence by geography may inform planning of public health measures to decrease congenital CMV.