Neonatal pain, parenting stress and interaction, in relation to cognitive and motor development at 8 and 18 months in preterm infants

TLDR

Procedural pain in the NICU triggers physiological, behavioral, and hormonal disruptions that may impair neurodevelopment in very preterm infants during a critical period of brain maturation. This study examined how cumulative skin‑breaking procedures relate to cognitive, motor, and behavioral outcomes at 8 and 18 months corrected age, and whether parenting stress modifies these associations. The prospective cohort included 211 infants (137 preterm at 32 weeks GA and 74 full‑term controls), excluding those with significant brain injury or major sensory impairments. Higher numbers of skin‑breaking procedures were independently associated with poorer cognition and motor function, correlated with ventilation days, and greater morphine exposure predicted worse motor development at 8 months but not 18 months, while lower parenting stress mitigated the pain effect on 18‑month cognition.

Abstract

Procedural pain in the neonatal intensive care unit triggers a cascade of physiological, behavioral and hormonal disruptions which may contribute to altered neurodevelopment in infants born very preterm, who undergo prolonged hospitalization at a time of physiological immaturity and rapid brain development. The aim of this study was to examine relationships between cumulative procedural pain (number of skin-breaking procedures from birth to term, adjusted for early illness severity and overall intravenous morphine exposure), and later cognitive, motor abilities and behavior in very preterm infants at 8 and 18 months corrected chronological age (CCA), and further, to evaluate the extent to which parenting factors modulate these relationships over time. Participants were N=211 infants (n=137 born preterm 32 weeks gestational age [GA] and n=74 full-term controls) followed prospectively since birth. Infants with significant neonatal brain injury (periventricular leucomalacia, grade 3 or 4 intraventricular hemorrhage) and/or major sensori-neural impairments, were excluded. Poorer cognition and motor function were associated with higher number of skin-breaking procedures, independent of early illness severity, overall intravenous morphine, and exposure to postnatal steroids. The number of skin-breaking procedures as a marker of neonatal pain was closely related to days on mechanical ventilation. In general, greater overall exposure to intravenous morphine was associated with poorer motor development at 8 months, but not at 18 months CCA, however, specific protocols for morphine administration were not evaluated. Lower parenting stress modulated effects of neonatal pain, only on cognitive outcome at 18 months.