CD40LG and cytomegalovirus infection: In this prospective cohort study of 300 pregnant women positive for CMV IgM, including 22 pregnant women who delivered newborns with congenital CMV infection, maternal serum CMV IgG avidity index; an antigenemia (C7-HRP) assay (CMV antigen test); CMV DNA PCR assays in the maternal serum, urine, and maternal uterine cervical secretion; and fetal ultrasound findings were evaluated.