Psychometric properties of the frequency of suicidal ideation inventory (FSII) in pregnant women: evidence from SEM, measurement invariance, and IRT models

Introduction – Suicidal ideation during pregnancy constitutes a significant public health concern due to its serious consequences for both the mother and the fetus. Despite its relevance, the accurate assessment of this construct in pregnant women remains limited, particularly in Latin American contexts. In this regard, having psychometrically sound and culturally appropriate instruments is essential for early detection and timely intervention. Objective – To analyze the psychometric properties of the Frequency of Suicidal Ideation Inventory (FSII) in pregnant women. Methods – A total of 962 Peruvian pregnant women participated, completing a sociodemographic questionnaire, the Frequency of Suicidal Ideation Inventory (FSII), the Athens Insomnia Scale (AIS), the Patient Health Questionnaire-2 (PHQ-2), and the Generalized Anxiety Disorder-2 (GAD-2). Structural equation modeling, Bayesian reliability, and item response theory were applied for statistical analysis. Results – The FSII demonstrated adequate content validity (V > 0.70), a unidimensional structure [CFI = 0.99, TLI = 0.99, RMSEA = 0.07 (90% CI: 0.050, 0.099), SRMR = 0.01], and high reliability (ω = 0.94, H = 0.98). Additionally, factorial invariance was supported according to pregnancy planning status, and significant positive associations were found with depressive symptoms, generalized anxiety, and insomnia. Item 4 showed the highest discrimination and information, and the scale proved to be most precise at higher levels of suicidal ideation. Conclusions – The FSII shows adequate psychometric properties that support its factorial structure and reliability for interpreting scores in Peruvian pregnant women. Evidence of factorial invariance by pregnancy planning and its utility at higher levels of suicidal ideation further support its use in this population. Therefore, its application is recommended in both clinical practice and research, contributing to the detection and prevention of suicidal risk during pregnancy.