目的·探讨不同程度小于胎龄儿（small for gestational age infant, SGA）母体的孕前及孕期高危因素。方法·纳入2013年9月—2016年12月在上海交通大学医学院附属新华医院分娩的母体及单胎新生儿，根据子代不同出生体质量所在百分位分为4组：轻度SGA组（SGA5th～10th）、中度SGA组（SGA3rd～5th）、重度SGA组（rd）、正常对照组。采用多变量Logistic回归分析SGA母体孕期及孕前高危因素与不同程度SGA发生的相关性。结果·母体的年龄、产次、受教育程度、早产发生率、胎儿性别与SGA无相关性。母体体质量指数（body mass index，BMI）、妊娠高血压和接受辅助生殖与SGA显著相关（均P结论·母体低BMI、妊娠高血压是中度SGA的高危因素，接受辅助生殖是重度SGA的高危因素；不同程度SGA的高危因素并不相同。

Objective · To explore the pregestational and gestational risk factors associated with small for gestational age infant (SGA)different degrees. Methods · Mothers and single newborns delivered at Xinhua Hospital, Shanghai Jiao Tong University School of Medicine September 2013 to December 2016 were included. Multivariate Logistic regression was used to analyze the correlation between maternal pregnancy and pre-pregnancy risk factors and the occurrence of SGAdifferent degrees. Results · There were no statistically significant differences in maternal age, number of birth, education level, incidence of preterm birth and fetal sex in SGA. Maternal body mass index (BMI), gestational hypertension and accepting assisted reproduction were significantly correlated with SGA (all PConclusion · Maternal low BMI and hypertension are the risk factors of moderate SGA and accepting assisted reproduction are the risk factors of severe SGA, and the risk factors of SGAdifferent degrees are not the same.