Modelling maternal cytomegalovirus seroprevalence in Australia using maternal country of birth: Implications for antenatal screening

Background: Cytomegalovirus (CMV) is the most common congenital infection and a leading preventable cause of neurodevelopmental disability. Contemporary maternal CMV seroprevalence estimates are needed to inform antenatal screening policy in Australia. Purpose: To estimate CMV seroprevalence among women referred for antenatal care at a tertiary maternity hospital, identify clinical and sociodemographic associations with serostatus, and model national and hospital-level seroprevalence by maternal country of birth. Materials and Methods: CMV serology results from GP antenatal referrals to a Melbourne tertiary hospital over 13 months were analysed. Seroprevalence was stratified by maternal country of birth, grouped by Organisation for Economic Co-operation and Development (OECD) membership. National and hospital-specific seroprevalence were modelled using Australian Bureau of Statistics and research dataset country-of-birth distributions. Results: Of 4377 referrals, 591 (12.5%) included CMV serology; 61.3% were CMV IgG positive. Median gestational age at testing was 5.4 weeks; referral occurred at a median of 9 weeks. Seroprevalence was higher among women born in non-OECD countries (86.6%) versus OECD countries (54.3%) (adjusted OR 6.44, P<0.001). Modelled national maternal seroprevalence was 63.6%. Across Melbourne public hospitals, estimates ranged from 60% to 74%, reflecting demographic variation. Among 328 women tested for CMV IgM, 17 (5.2%) had positive or equivocal results; one had low avidity IgG, consistent with recent primary infection. Conclusions: Maternal CMV seroprevalence in this cohort is higher than previously reported and strongly associated with maternal country of birth. These data inform evaluation of antenatal CMV screening feasibility and cost-effectiveness studies in Australia.