Abstract: Objective To explore the risk factors for full-term infants born small for gestational age(SGA)of different severities and the impact of SGA on neonatal behavioral neurological assessment(NBNA). Methods A retrospective study was conducted. A total of 148 term SGA born in Fuzhou First General Hospital were enrolled as the observation group(107 mild and 41 severe), and 152 non-SGA were enrolled as the control group. Maternal and neonatal baseline data were collected, and NBNA was performed at 3-7 days after birth. The study was divided into two modules:(1)For risk factor analysis, all 300 neonates were included, and ordinal multinomial logistic regression was used to analyze the risk factors for different severities of SGA.(2)For NBNA score influencing factors, only the 148 SGA were included, and univariate analysis and multiple linear regression were used to analyze the effects of neonatal factors on the total NBNA score. Results Through ordinal multinomial logistic regression, hypertensive disorders of pregnancy(OR=5.595, 95%CI: 2.166-14.902, P<0.001), oligohydramnios(OR=1.848, 95%CI: 1.463-2.338, P<0.001), and low maternal education level(OR=0.679, 95%CI: 0.537-0.859, P=0.001)were identified as independent risk factors for the severity of term SGA, while prepregnancy body mass index(BMI)was not found to be statistically significant(OR=0.908, 95%CI: 0.808-1.017, P=0.100). The total NBNA scores among the three groups were compared, and significant differences were observed between groups(P<0.001), with scores in the non-SGA group(37.11±0.87)higher than those in the mild SGA group(36.51±1.09)and severe SGA group(36.03±1.24). After confounding factors were adjusted for by multiple linear regression, active muscle tone(b=0.745, P<0.001)and passive muscle tone(b=0.524, P=0.003)were found to be independently associated with NBNA total scores. Conclusion Hypertensive disorders of pregnancy, oligohydramnios, and low maternal education level are confirmed as independent risk factors for the severity of term SGA. Early neurobehavioral development in neonates is found to be affected by SGA, and the NBNA score is decreased with increasing severity of SGA. The effect of SGA on NBNA may be mainly mediated by muscle tone.

Key words: small for gestational age infant, risk factors, hypertensive disorders of pregnancy, neonatal behavioral neurological assessment, muscle tone