Skin-to-skin contact improves sleep stability in preterm infants.

Abstract

Sleep supports neurophysiological maturation in preterm infants, yet the impact of developmental care interventions on sleep remains poorly quantified. Skin-to-skin contact (SSC) improves physiological stability, but its effects on sleep structure measured with automated methods are unclear. We hypothesized that SSC increases sleep duration and reduces sleep fragmentation. In this prospective observational study (September 2024-May 2025), clinically stable preterm infants born at 29 + 0 to 33 + 6 weeks' gestation were enrolled in a level III Neonatal Intensive Care Unit. Infants with major congenital anomalies or recent exposure to sedatives or analgesics were excluded; caffeine therapy was allowed. Each infant received ≥1 hour of SSC. Cardiorespiratory monitoring data were analyzed using a validated machine-learning algorithm to classify sleep states across three hour-epochs: before, during, and after SSC. Primary outcomes were sleep-state proportions and approximate entropy (ApEn). 61 infants contributed to 91 recordings. SSC shifted the wake-sleep balance toward sleep dominance. ApEn decreased after SSC, indicating greater regularity and stabilization of sleep-wake transitions. Higher gestational age was independently associated with lower ApEn, consistent with maturational stabilization of sleep architecture. SSC is associated with more continuous and stable sleep in preterm infants. Automated physiologic monitoring provides a non-invasive method to quantify developmental care effects and may offer sensitive markers of neurophysiological regulation. Skin-to-skin contact in preterm infants is associated with less wakefulness and reduced sleep fragmentation, with effects persisting beyond the period of contact, indicating a more stable sleep-wake organization. The study provides quantitative evidence that skin-to-skin contact influences sleep organization in preterm infants, demonstrating effects not only during the intervention but also in the subsequent period. These findings strengthen the physiological rationale for skin-to-skin contact by showing that it supports more stable sleep, a central behavioural state linked to early brain development in preterm infants.