Psychometric properties and measurement invariance of the Childbirth Trauma Index scale in Chinese parturients of reproductive age

Background Psychological birth trauma not only endangers maternal physical and mental health but also has negative impacts on the family and society. Therefore, screening for psychological birth trauma is the critical first step of any intervention strategy. However, existing PBT tools lack cross-cultural validity and equivalence assessment, and overlook key perinatal-specific stressors and non-typical symptoms. The Childbirth Trauma Index Scale(CTIS) addresses these gaps with culturally adapted items covering salient trauma sources, providing a reliable auxiliary measure for diverse parturient populations. The purpose of this study was to evaluate the psychometric properties and measurement invariance of the Chinese version of the CTI scale among Chinese parturients of reproductive age. Method A convenience sample of 362 parturient women of reproductive age was recruited from several tertiary hospitals in Sichuan Province. All participants were then assessed for childbirth-related trauma using the Childbirth Trauma Index (CTI).Criterion measures included the Family APGAR and the Patient Health Questionnaire-4 (PHQ-4). Reliability, validity, and cross-group measurement invariance were evaluated. Validity was examined through structural and concurrent validity. Multigroup confirmatory factor analyses were performed to test measurement invariance across age, education level, and delivery mode. Result The Chinese version of the CTIS includes three factors with 14 items. The CTIS exhibited excellent internal consistency (Cronbach's alpha was 0.80, factor alphas were 0.72, 0.85, and 0.68, respectively; McDonald's omega was 0.82). The CTIS exhibited stable structural validity and the confirmative factor analysis showed that the comparative fit index (CFI), incremental fit and Tucker-Lewis Index (TLI) were all above 0.9, RMSEA below 0.08, indicating a good model fit. The measurement invariance of the CTIS across ages, education levels, and delivery mode was supported by its metric invariance, scalar invariance and residual invariance. The CTI scores show significant negative correlations with APGAR and resilience, and significant positive correlations with anxiety and depression. Conclusion The CTIS proved to be a suitable tool for assessing postpartum birth trauma among Chinese parturients of reproductive age.