Cross-cultural adaptation of the Postpartum Bonding Questionnaire (PBQ) to Brazil: assessment of the measurement properties of construct validity and reliability

To evaluate the measurement properties of construct validity and reliability of the Brazilian Portuguese version of the Postpartum bonding questionnaire (PBQ). The PBQ was applied 1 to 8 months after birth in a cohort of 489 mothers and babies followed from pregnancy to postpartum. To assess structural validity, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were carried out through structural equation models (SEM), using the robust weighted least squares estimator (WLSMV) and oblique rotation. The Comparative fit index (CFI), Tucker-Lewis index (TLI), and root of the mean square error of approximation (RMSEA) were used to verify model adequacy, and composite reliability (CR) by factor to assess internal consistency. Given the moderate association between the factors and theoretical evidence of a general factor of the construct, a second order factor analysis was performed. A hierarchical factorial model was found, with a second order factor, three first order factors ("Lack of joy and pleasure", "Rejection and anger" and "Anxiety and risk of abuse") and 12 items. The adjustment indexes proved to be adequate (CFI = 0.983, TLI = 0.978 and RMSEA 0.031, IC = 0.013-0.045). The three dimensions showed good internal consistency (CR = 0.835, 0.792, and 0.691 respectively), indicating good reliability. The final Brazilian version of PBQ showed adequate measurement properties of construct validity and internal consistency, providing a promising and unprecedented instrument for use in scientific research and clinical assistance in Brazil.