Neurobehavior of preterm infants from 32 to 48 weeks post-menstrual age.

Aim: Evaluate prospectively the neurobehavior of preterm infants (PT).
Study Design: Cohort of PT (gestational age(GA) <32weeks), evaluated biweekly from 32 to 48 weeks post-menstrual age (PMA) by NICU Network Neurobehavioral Scale (NNNS). Scores were compared by repeated Measures ANOVA. Scores of PT were compared to those of full-term infants, matched for gender by ANOVA.
Results: 39 PT (mean ± SD: GA 29.2 ± 2.0 weeks; birthweight 1100 ± 331g) were studied. As PMA progressed, PT showed increasing scores in habituation, attention, arousal, regulation, maneuvers for orientation, quality of movements and hypertonicity, and decreasing scores in excitability, lethargy, non-optimal reflexes, asymmetry, hypotonicity, and signs of stress/withdrawal. At 40 weeks PMA, PT were similar to term neonates assessed in the first days of life, except for less habituation, regulation capacity and excitability, and more hypotonia.
Conclusion: At 40 weeks PMA, PT reached the performance of full-term neonates evaluated in the first days of life in most neurobehavior domains.