Longitudinal Changes in Caregiver Psychological Well-Being and Infant Temperament Following Preterm Birth: From Enrollment to 12 Months Corrected Age

Background: Advances in neonatal care have substantially improved the survival of preterm infants; however, longitudinal changes in caregiver psychological well-being and infant temperament during follow-up remain incompletely understood. This study aimed to characterize changes in caregiver psychological measures and infant temperament from enrollment through 12 months corrected age (CA) and to explore their clinical and socioeconomic correlates. Methods: This prospective longitudinal cohort study included 35 preterm infant–parent dyads assessed at enrollment (mean CA, 2.3 ± 1.3 months), 6 months CA, and 12 months CA. The same parent completed measures of depressive symptoms (Korean Beck Depression Inventory-II [K-BDI-II]), parenting stress (Korean Parenting Stress Index, Fourth Edition [K-PSI-4]), general self-efficacy, and infant temperament (Infant Behavior Questionnaire–Revised [IBQ-R]) across available assessments. Developmental outcomes were assessed using the Bayley Scales of Infant Development, Second Edition (BSID-II) at 12 months CA. Longitudinal changes were analyzed using linear mixed-effects models with false discovery rate (FDR) correction across the eight domain-level questionnaire outcomes comprising the main longitudinal analysis family; additional analyses were exploratory. Results: K-BDI-II depressive symptom scores (FDR q = 0.022) and K-PSI-4 Parent-domain stress (q = 0.011) decreased over time, whereas Total Stress, Child-domain stress, and general self-efficacy did not change significantly. Infant Surgency/Extraversion (q < 0.008) and Negative Affectivity (q = 0.008) increased, whereas Orienting/Regulation did not change significantly. No associations between clinical or socioeconomic characteristics and study outcomes remained significant after FDR correction. At 12 months CA, K-PSI-4 Total Stress was positively correlated with parent-reported infant Negative Affectivity (r = 0.47, q = 0.039). Conclusions: Caregiver psychological measures and infant temperament showed distinct longitudinal changes from enrollment through 12 months CA following preterm birth. Repeated assessment of caregiver psychological well-being may complement developmental follow-up of preterm infants. These within-cohort findings, particularly the exploratory associations, require confirmation in larger and more diverse longitudinal cohorts.