Measuring health literacy for maternal health surveillance: psychometric validation of the Portuguese HLS19-Q12 among pregnant women.

Health literacy is a modifiable determinant of maternal health and an important condition for equitable access to antenatal information, shared decision-making, and preventive care. Reliable and brief instruments are needed to monitor health literacy during pregnancy and to guide public health interventions. This study validated the Portuguese version of the 12-item European Health Literacy Survey questionnaire (HLS19-Q12) among pregnant women and examined its psychometric properties among pregnant women. A descriptive cross-sectional psychometric study was conducted with 886 pregnant women recruited through antenatal care services in Portugal. Factorial validity was assessed using exploratory factor analysis and confirmatory factor analysis with the diagonally weighted least squares (DWLS) estimator; reliability was evaluated using Cronbach's alpha and McDonald's omega; and construct validity was examined through correlations with digital and navigational health literacy indices. The results supported a unidimensional structure for the HLS19-Q12 [χ2(50) = 221.77, p < 0.001; CFI = 0.993; TLI = 0.991; RMSEA = 0.062, 90% CI (0.054, 0.071); SRMR = 0.046]. Standardized factor loadings ranged from 0.59 to 0.80. Internal consistency was high (α = 0.86; ω = 0.87), and moderate positive correlations with digital (r = 0.65) and navigational (r = 0.61) health literacy supported convergent validity. The Portuguese HLS19-Q12 is a valid and reliable instrument for assessing general health literacy among pregnant women. Following further validation and implementation research, the Portuguese HLS19-Q12 may have potential to support population monitoring of general health literacy among pregnant women and to inform targeted public health interventions.