Object of the investigation - estimation of changes of the feto-placental complex and syncytiotrophoblaston based on the placental morphology and the activity of the antiviral antibodies in expectant mothers. The work is based on findings from 50 expectant mothers with cytomegalovirus (CMV) infection - 43 with reactivation of the latent infection according to the data of high avid IgG (86%) and 7 with primary active CMV infection according the level of the low avid IgG (14%). 20 healthy expectant mothers were included in the control group. It was shown that the active primary and reactivated CMV infection accompanied by the drawing in pathologic process the chorion structures in a productive inflammation - chorionamnionis and choriovillusitis manner, which testify to drawing the fetus immune system in reciprocal reaction with subsequent intrauterine growth retardation.