Objective: This study aims to explore the occurrence of extrauterine growth retardation (EUGR) in preterm infants with a gestational age of <34 weeks, at discharge, and the factors influencing the occurrence of EUGR.Method: A retrospective analysis of 691 preterm infants with a gestational age of less than 34 weeks, born in our hospital over the past 3 years. At discharge, the growth indicators head circumference, weight, and length were used to divide the infants into an EUGR group (n = 255) and the non-EUGR group (n = 436). The occurrence of EUGR and its influencing factors were then analyzed.Results: Of the 691 preterm infants evaluated for inclusion in the study, 255 cases (36.9%) met the requirements of EUGR at discharge. The different growth indicators used, i.e., weight, length, and head circumference, classified the infants differently. The incidence of EUGR using these measures was 30.2% (209), 27.9% (193), and 23.2% (161), respectively. The results of a univariate analysis showed that gestational age, birth weight, intrauterine growth retardation (IUGR), maternal gestational hypertension, age at which the infant commenced feeding, duration of the application of an invasive ventilator, length of hospital stay, nosocomial infection, respiratory and gastrointestinal diseases, symptomatic patent ductus arteriosus, and the early onset of neonatal sepsis were correlated with the occurrence of EUGR. Further logistic multivariate regression analysis revealed that low gestational age, low birth weight, complicated IUGR, respiratory distress syndrome, and necrotizing enterocolitis were independent risk factors for EUGR in preterm infants with a gestational age <34 weeks.Conclusion: In preterm infants with a gestational age <34 weeks in our hospital, there is a high incidence of EUGR, which is affected by factors such as the gestational age, birth weight, IUGR, respiratory distress syndrome, necrotizing enterocolitis, and other factors.