GABBR2 and cytomegalovirus infection: <h4>Objective</h4>To estimate the residual risk of maternal-fetal transmission after primary cytomegalovirus (CMV) infection in the periconceptional period or the first trimester in women treated with valacyclovir, and to assess whether the presence of glycoprotein B2 (gB2)-specific immunoglobulin (Ig)-G antibodies on immunoblot analysis refines fetal risk prediction.<h4>Methods</h4>This was a retrospective single-center study conducted at University Hospital Tübingen, Tübingen, Germany, between October 2023 and June 2025.