<![CDATA[Background: Maternal anxiety during the third trimester is an important psychosocial concern and may be associated with physiological stress responses. Purpose: To analyze the associations of psychosocial determinants with maternal anxiety and cortisol concentrations among third-trimester pregnant women. Method: A quantitative observational analytic study was conducted among 120 third-trimester pregnant women in Sleman Regency, Yogyakarta, Indonesia, in 2025. Maternal knowledge, pregnancy perceptions, family support, and healthcare provider support were assessed using questionnaires. Anxiety was measured using the State-Trait Anxiety Inventory-State (STAI-S), while salivary cortisol was measured using enzyme-linked immunosorbent assay (ELISA). Bivariate analysis and multiple linear regression were performed. Results: Knowledge, perceptions, family support, and healthcare provider support were significantly associated with lower maternal anxiety (p<0.001). In multivariable analysis, knowledge (β=-0.192; p=0.026), perceptions (β=-0.251; p=0.002), family support (β=-0.387; p<0.001), and healthcare provider support (β=-0.176; p=0.030) independently predicted anxiety (R²=0.48). The same psychosocial factors were associated with lower cortisol concentrations. Maternal anxiety was positively correlated with cortisol concentrations (r=0.512; p<0.001) and was the strongest predictor of cortisol (β=0.391; p<0.001; R²=0.55). Conclusion: Better psychosocial conditions, particularly stronger family support, were associated with lower maternal anxiety and cortisol concentrations. Integrating psychosocial assessment, anxiety screening, maternal education, and family involvement may strengthen comprehensive antenatal care. Keywords: Antenatal Care; Cortisol; Family Support; Maternal Anxiety; Pregnancy; Psychosocial Determinants; Third Trimester. ]]>
