Factor structure and longitudinal invariance for the Chinese Mainland version of the Edinburgh postnatal depression scale during pregnancy.

BACKGROUND: There are inconsistent results on the Edinburgh Postnatal Depression Scale's (EPDS) factor structure and longitudinal invariance among different cultures. Furthermore, limited relevant studies in Chinese pregnant women exist.

PURPOSE: To test the factor structure of the Chinese Mainland EPDS during pregnancy and conduct longitudinal invariance analyses.

METHODS: A national multi-centre cohort study was conducted among 1207 pregnant women selected consecutively by convenience sampling from five hospitals in Zhuhai, Taiyuan, Haidian, Changchun, and Shenzhen in China between August 2015 and October 2016. Depression was measured by the EPDS during gestational weeks 10-13, 15-18, 23-25, 30-32 and 36-37, respectively.s RESULTS: Three factors with eigenvalues nearly larger than 1.0 were optimal for the Chinese Mainland EPDS, labelled "anxiety," "anhedonia," and "depression," and contained items 3-5, 1-2, and 6-10, respectively. The confirmatory factor analysis results of standardized root mean square residual (SRMR) = 0.034, root mean square error of approximation (RMSEA) = 0.049, comparative fit index (CFI) = 0.968, Tucker-Lewis index (TLI) = 0.954, and χ2 , p < 0.05 indicated good fit. For the longitudinal invariance tests, the configural invariance was met, with the CFI and TLI both higher than 0.90 and the RMSEA lower than 0.08 (CFI = 0.919, TLI = 0.908, and RMSEA = 0.034). The metric-, scalar-, and strict invariances were met.

CONCLUSIONS: The three-factor model of the Chinese Mainland EPDS is invariant in pregnancy, suggesting stability and comparability in identifying the women screened positive at different points during pregnancy and making the scale feasible to screen prenatal depression and anxiety simultaneously.