Abstract: Objective To explore the difference of neurobehavioral development among children of different birth and gestational ages. Methods Neonates born in Northwest Women's and Children's Hospital from January 1, 2019 to June 30, 2020 were selected by random sampling method, and were divided into premature infants group （gestational age 28-36 weeks）, early infants group （gestational age 37-38 weeks）, and term infants group （gestational age ≥ 39 weeks） according to gestational age. Neonatal Behavioral Neurological Assessment （NBNA） was performed in premature and early infants at 40 weeks of corrected gestational age and in term infants at 24 hours after birth. At 6 months, 12 months, and 24 months after birth, premature infants, early infants, and term infants were followed up to evaluate their neuropsychological development level using the Neuropsychological Development Scale for Children Aged 0-6 from Beijing Capital Children's Research Institute. Results There were 986 newborns in this study. There were 122 premature infants, including 54 males and 68 females, with an average gestational age of （32.42 ± 1.54） weeks; 275 early infants, including 122 males and 153 females, with an average gestational age of （37.54 ± 1.21） weeks; 589 term infants, including 245 males and 344 females, with an average gestational age of （39.89 ± 0.52） weeks. At the age of 6 months, the scores of total development quotient, gross motor, fine motor, cognition, language, and social interaction in premature infants and early infants were significantly lower than those in term infants （all P<0.01）. At the age of 12 months and 24 months, the scores of total development quotient, gross motor, fine motor, cognition, language, and social interaction in premature infants were significantly lower than those in term infants （all P<0.01）. The gestational age was positively correlated with the scores of gross motor, fine motor, cognition, language, and social interaction （all P<0.05）. The older the gestational age was, the higher the scores of gross motor, fine motor, cognition, language, and social interaction were （r=0.992, 0.968, 0.955, 0.933, 0.990）. Conclusions The neurobehavioral development levels of postnatal premature infants and early infants are significantly lower than that of term infants. The neuropsychological development levels of 6-month-old premature infants and early infants are significantly lower than that of term infants. The neuropsychological development levels of 12-month-old and 24-month-old premature infants are still significantly lower than that of term infants, but the early infants are equivalent to that of term infants.

Key words: Premature infant, Early infant, Gestational age, Neurobehavioral development