Hyperimmune globulin therapy given to pregnant women with a cytomegalovirus (CMV) infection fails to protect their babies from congenital CMV infection or perinatal death, a study shows.

Congenital CMV infection is associated with stillbirth, neonatal death, deafness, and cognitive and motor delay among symptomatic offspring, the researchers note in their article in the New England Journal of Medicine.

The trial of the expensive and time-consuming monthly treatment was stopped early for futility after 23% of the children in the hyperimmune globulin group became infected or died — either in utero or shortly after birth.

This compared with 19% of the babies whose mothers received a monthly placebo infusion up to delivery.