Psychometric analysis and validation of the SF-34 PREG: An adaptation of the SF-36 for assessing quality of life in pregnant women.

Objective: This study aims to perform a psychometric analysis of the 36-item short form health survey (SF-36) in a population of pregnant women and validate an adapted version of the instrument to measure health-related quality of life specific to pregnancy.
Methods: A cross-sectional study design was carried out with data collection between 7 and 36 weeks of gestation, with a total sample of 547 pregnant women divided into two randomized subsamples. Data were collected between September 2021 and April 2023. An exploratory factor analysis was initially performed on one subsample, followed by a confirmatory factor analysis on the other. Internal consistency was assessed using Cronbach's alpha and McDonald's omega, and correlations between factors were analyzed.
Results: Results from the exploratory factor analysis proposed a seven-factor model explaining 56% of the variance. All proposed dimensions achieved Cronbach's alpha scores above 0.75, with a total test score of 0.92. Furthermore, all dimensions exhibited positive and statistically significant correlations. Bartlett's test of sphericity and the Kaiser-Meyer-Olkin test yielded values of 5599 (P < 0.001) and 0.871, respectively. The confirmatory factor analysis reaffirmed this model with good fit indices: χ ² 792 (P < 0.001), comparative fit index (CFI) and Tucker-Lewis index (TLI) >0.90, and standardized root mean square residual (SRMR) and root mean square error of approximation (RMSEA) <0.06.
Conclusion: This study developed and validated the "SF-34 PREG," an adapted version of the SF-36, specifically designed for pregnant women. The SF-34 PREG demonstrated high reliability and a robust factorial structure, making it a more precise and relevant tool for assessing health-related quality of life during pregnancy. Although it does not include the social functioning dimension of the original SF-36, the SF-34 PREG offers improved relevance and accuracy for this specific population. Further research and clinical use of the SF-34 PREG are recommended.
(© 2024 The Author(s). International Journal of Gynecology & Obstetrics published by John Wiley & Sons Ltd on behalf of International Federation of Gynecology and Obstetrics.)