To examine the effect of the interval between maternal cytomegalovirus (CMV) infection and conception on the risk of congenital CMV infection, the congenital CMV infection rate was evaluated relative to the intervals between deliveries in young women. Among mothers who seroconverted between deliveries, the rate of congenital CMV infection among their offspring was highest when the delivery interval was < or =24 months. However, the risk of transmission remained elevated for women with delivery intervals of 25-48 months and for those with delivery intervals >48 months apart.