Universal Cytomegalovirus Screening in the First Trimester of Pregnancy: The Multicentre Observational Cohort Study in the Area of Barcelona (CITEMB Study)

Abstract

Objective: To determine the CMV seroprevalence among pregnant women and assess the rate of primary CMV infections during the first trimester. Design: Prospective multicentre observational cohort study. Setting: Four primary care centres (ASSIRs) and two tertiary hospitals in Barcelona and its metropolitan area. Pupulation or Sample: Pregnant women attending first-trimester antenatal visits between October 2022 and September 2024. Methods: All participants underwent CMV IgG and IgM serological testing at the first antenatal visit. Women with positive IgM and low or intermediate IgG avidity were diagnosed with primary CMV infection and managed according to local protocols, including treatment with valaciclovir and fetal follow-up. Main Outcome Measures: CMV screening acceptance rate, seroprevalence, rate of primary infection, fetal infection, and neonatal outcomes up to one year of age. Results: Of 3 677 pregnant women recruited, 3 357 were included in the final analysis. CMV screening acceptance was high. Seroprevalence was 77.7% (95% CI 76.2%–79.1%), and 743 women (22.1%, 95% CI 20.7%–23.6%) were seronegative. Five cases (0.15%, 95% CI 0.05%–0.37%) of primary CMV infection were identified and treated. No fetal infections were detected by amniocentesis. One newborn tested positive for CMV but remained asymptomatic at birth and at 6 months. Women who were seronegative were generally older, of European origin, and had higher education and employment rates. Conclusions: Universal first-trimester CMV screening is feasible and well accepted in a public healthcare setting. While the rate of primary infection was low, early identification of seronegative women offers opportunities for preventive counselling and targeted follow-up.