Abstract
BACKGROUND AND OBJECTIVES: Preterm birth is associated with altered white matter development and long-term neurodevelopmental impairments. Skin-to-skin care has known benefits for physiologic regulation and bonding in preterm infants, but impacts on early brain structure remain unclear. The aim of this study was to describe the association between in-hospital skin-to-skin care and white matter microstructure in very preterm infants, focusing on frontolimbic tracts involved in stress regulation and socioemotional development. METHODS: The design was a single-center retrospective observational analysis of clinical data from the electronic medical records and diffusion MRI scans. Participants were infants born at <32 weeks gestational age (GA) who received a routine predischarge MRI. Skin-to-skin care was quantified as duration per instance and daily exposure rate (in minutes) before the MRI was obtained. Diffusion MRI assessed mean diffusivity (MD) and fractional anisotropy (FA) in the cingulum, anterior thalamic radiations (ATRs), and uncinate fasciculus. Hierarchical regression models evaluated associations between skin-to-skin care and white matter metrics, adjusting for GA, medical acuity, postmenstrual age at scan, and MRI coil type. RESULTS: A total of 88 preterm infants (mean GA 29 weeks; 49% female) were included. Skin-to-skin care duration per instance was positively associated with MD in the cingulum (B = 0.002, 95% CI 0.0004-0.003, ΔR(2) = 0.080) and ATRs (B = 0.002, 95% CI 0.0003-0.003, ΔR(2) = 0.057). Skin-to-skin care daily exposure rate was also positively associated with ATR MD (B = 0.038, 95% CI 0.001-0.076, ΔR(2) = 0.046). Both skin-to-skin metrics were negatively associated with ATR FA (duration: B = -0.0005, 95% CI -0.001 to -0.0001, ΔR(2) = 0.046; rate: B = -0.016, 95% CI -0.028 to -0.004, ΔR(2) = 0.075). No significant associations were found for the uncinate fasciculus. Findings remained significant after adjusting for socioeconomic status and visitation frequency and after excluding infants with white matter injury. DISCUSSION: Skin-to-skin care was associated with neonatal white matter microstructure in specific frontolimbic tracts. Limitations include the retrospective design and single-center setting. Future studies should consider how early caregiving experiences, such as skin-to-skin care, may influence brain development in preterm infants.