Objectives: To investigate the possibility of the births of small for gestational age (SGA) infant in patients with risk factors.Methods: This study enrolled 3046 babies born between 2005 and 2007. The cases were divided into the small for gestational age (SGA) group (312 cases) and the control group (2734 cases). A multivariable analysis was conducted to retrospectively analyze the factors associated with low fetal birth weight, which include abnormalities of the neonate, placenta and umbilical cord, and maternal complications.Results: The odds ratios (99% confidence interval) of SGA were 5.3 (3.4-8.3) for multiple pregnancy, 2.4 (1.2-4.7) for fetal malformation, 4.6 (2.0-10.5) for velamentous cord insertion, 2.0 (1.0-3.8) for marginal cord insertion, 3.7(2.0-6.9) for hypercoiled cord, 5.3 (3.2-9.0) for pregnancy induced hypertension, and 1.8 (1.2-2.6) for low maternal body mass index (BMI<18.5). Conclusion: A multivariable analysis was conducted to determine the odds ratios for the birth of an SGA infant -for various risk factors of fetal growth restriction. These data might improve the prognosis of infants through the intensive perinatal management.