目的 探讨早产小于胎龄儿（SGA）与适于胎龄儿（AGA）在住院期间生长代谢的差异，为临床对早产SGA进行营养干预提供依据。方法 1 370例早产儿纳入研究，根据胎龄与出生体重的关系分为SGA组（675例）与AGA组（695例），比较两组早产儿住院期间的一般情况、体格增长及血生化指标等情况。结果 SGA组住院天数长于AGA组（P < 0.05）。与AGA组相比，SGA组出院体重、出院体重Z评分及出院身长均较低，宫外生长迟缓发生率较高（P < 0.05），头围增长速率大于AGA组。与AGA组相比，SGA组达全肠内喂养时间及需肠外营养时间均较长（P < 0.05）。SGA组入院时白蛋白、前白蛋白、血清磷、出院前总胆汁酸高于AGA组，白蛋白低于AGA组（P < 0.05）。SGA组窒息、新生儿呼吸窘迫综合征、心肌损伤、喂养不耐受、肺炎、败血症、低血糖、低甲状腺素血症的发生率高于AGA组（P < 0.05）。结论 早产SGA住院期间体格发育明显落后于AGA，宫外生长迟缓发生率较高，更易出现并发症。

Objective To study the differences in growth and metabolism between small for gestational age (SGA) infants and appropriate for gestational age (AGA) infants. Methods A total of 1 370 preterm infants were enrolled in this study. According to the association between gestational age and birth weight, they were divided into SGA group with 675 infants and AGA group with 695 infants. The two groups were compared in terms of general conditions, physical growth and blood biochemical parameters. Results The SGA group had a significantly longer length of hospital stay than the AGA group (P < 0.05). Compared with the AGA group, the SGA group had significantly lower body weight, body weight Z score, and body length at discharge and significantly higher incidence rate of extrauterine growth retardation and growth rate of head circumference (P < 0.05). Compared with the AGA group, the SGA group had significantly longer time to full enteral nutrition and duration of parenteral nutrition (P < 0.05). Compared with the AGA group, the SGA group had significantly higher levels of albumin, prealbumin, and serum phosphorus on admission and total bile acid before discharge, as well as a significantly lower albumin level before discharge (P < 0.05). The incidence rates of asphyxia, neonatal respiratory distress syndrome, myocardial damage, feeding intolerance, pneumonia, sepsis, hypoglycemia and hypothyroxinemia in the SGA group were significantly higher than in the AGA group (P < 0.05). Conclusions Compared with AGA infants, SGA infants have significantly delayed physical development during hospitalization and significantly higher incidence rates of extrauterine growth retardation and related complications.