RESUMO
BACKGROUND: Neonatal Intensive Care Units (NICUs) protect preterm infants; otherwise, this is a stressful environment including painful stimuli. AIMS: To compare early neurobehavioral development prior to term-age in preterm infants at 34-36weeks of post-conceptional age in different gestational ages, and to examine the effects of prematurity level and acute stressful events during NICU hospitalization on neurobehavioral development. STUDY DESIGN: Cross-sectional design. SUBJECTS: Forth-five preterm infants, 34-36weeks of post-conceptional age, were distributed into groups: extreme preterm (EPT; 23-28weeks of gestational age; n=10), moderate preterm (MPT; 29-32weeks of gestational age; n=10), late preterm (LPT; 34-36weeks of gestational age; n=25). OUTCOME MEASURES: All of the neonates were evaluated using the Neurobehavioral Assessment of Preterm Infant (NAPI) prior to 37weeks of post-conceptional age. The Neonatal Infant Stressor Scale (NISS) was applied for EPT and MPT infants during NICU hospitalization, and medical charts were analyzed. RESULTS: The EPT group experienced significantly more acute stressful events during NICU hospitalization than the MPT group. The MPT group had lower scores in motor development and vigor than the EPT and LPT group, and they exhibited poorer quality crying than the LPT group. Motor development and vigor and alertness and orientation in preterm infants were predicted by prematurity level and acute stressful events. CONCLUSION: The extreme preterm was exposed to higher stressful experiences than moderate and late preterm infants. However, the moderate preterm infants presented more vulnerable than the other counterparts in motor and vigor outcomes.