Demographic and therapeutic determinants of pain reactivity in very low birth weight neonates at 32 Weeks' postconceptional Age.

BACKGROUND: Management of pain in very low birth weight infants is limited by a lack of empiric knowledge about the multiple determinants of biobehavioral reactivity in infants receiving neonatal intensive care. OBJECTIVE: To examine relationship of early neonatal factors and previous medication exposure to subsequent biobehavioral reactivity to acute pain of blood collection. DESIGN: Prospective cohort study. Methods. One hundred thirty-six very low birth weight (