目的 探究小于胎龄（SGA）儿发生坏死性小肠结肠炎（NEC）的危险因素。方法 选择2008年1月至2021年12月住院患NEC的SGA新生儿为研究对象;选择同期住院的未患NEC的SGA新生儿为对照组,按照孕周相差<3 d、出生体重相差<200 g、入院日期相差<3 月的条件进行1:2匹配。采用条件logistic回归分析SGA新生儿发生NEC的影响因素。结果 研究期间共收治5 365例SGA新生儿,其中符合NECⅡ期及以上诊断标准的147例,发生率为2.70%,经筛选排除后最终纳入140例;对照组按1:2匹配共选取280例。与对照组相比,NEC组贫血、新生儿败血症、病死或放弃治疗比例较高,住院时间较长,产前使用糖皮质激素、口服益生菌比例较低,差异有统计学意义（P<0.05）。条件logistic回归分析结果发现,败血症、贫血为SGA新生儿患NEC的独立危险因素（P<0.05）,而产前糖皮质激素暴露、口服益生菌则是其独立保护因素（P<0.05）。结论 SGA新生儿存在贫血、败血症更容易发生NEC,而口服益生菌、产前使用糖皮质激素可降低NEC发生的风险。

Objective To explore the risk factors of necrotizing enterocolitis (NEC) in small for gestational age (SGA) neonates. Methods The SGA patients suffering from NEC from January 2008 to December 2021 were selected as the research subjects. The SGA patients without NEC in the same period were selected as the control group, and 1∶2 matching was performed according to gestational age difference <3 d, birth weight difference <200 g, and date of admission difference <3 months. The influencing factors of NEC occurrence in SGA neonates were analyzed by conditional logistic regression. Results A total of 5 365 SGA neonates were admitted during the study period, among whom 147 SGA neonates met the diagnostic criteria of NEC stage Ⅱ or above, and the incidence rate was 2.70%. After screening and exclusion, 140 patients were finally included. A total of 280 SGA neonates were involved in the control group by 1∶2 matching. Compared with the control group, the NEC group had higher rates of anemia, neonatal sepsis, death or treatment abandonment, longer hospital stay, and lower rates of prenatal exposure to glucocorticoids and oral probiotics, and the differences were statistically significant (P<0.05). Conditional logistic regression analysis showed that sepsis and anemia were independent risk factors for NEC in SGA (P<0.05), while prenatal glucocorticoids exposure and oral probiotics were independent protective factors (P<0.05). Conclusions The SGA neonates with anemia and sepsis are more likely to develop NEC, while oral probiotics and prenatal exposure to glucocorticoids can reduce the risk of NEC..