目的 了解我国住院极早产儿（very preterm infant，VPI）宫外生长迟缓（extrauterine growth restriction，EUGR）的发生率及影响因素。 方法 采用多中心前瞻性调查研究方法，纳入2019年9月至2020年12月我国7个地区28家医院新生儿科的2 514例VPI临床资料，根据纠正胎龄36周或出院时的体重评估是否发生EUGR，分成EUGR组（n=1 189）和非EUGR组（n=1 325）。比较两组VPI的临床特征，探讨EUGR的发生情况及相关因素。 结果 以体重评价，EUGR的发生率为47.30%（1 189/2 514）。多因素logistic结果显示，恢复出生体重后平均体重增长速率快和住院第1周累计热卡高是EUGR的保护因素（P<0.05），小于胎龄儿、达全肠内营养所需时间长、累计禁食时间长、开始添加母乳强化剂时的母乳量少及达到全强化的所需时间长、中-重度支气管肺发育不良是EUGR发生的危险因素（P<0.05）。 结论 尽早达全肠内营养，及时强化母乳喂养，增加生后第1周的热卡摄入，提高体重增长速率，以及防治中-重度支气管肺发育不良对降低VPI EUGR的发生率至关重要。

Objective To investigate the incidence of extrauterine growth retardation (EUGR) and its risk factors in very preterm infants (VPIs) during hospitalization in China. Methods A prospective multicenter study was performed on the medical data of 2 514 VPIs who were hospitalized in the department of neonatology in 28 hospitals from 7 areas of China between September 2019 and December 2020. According to the presence or absence of EUGR based on the evaluation of body weight at the corrected gestational age of 36 weeks or at discharge, the VPIs were classified to two groups: EUGR group (n=1 189) and non-EUGR (n=1 325). The clinical features were compared between the two groups, and the incidence of EUGR and risk factors for EUGR were examined. Results The incidence of EUGR was 47.30% (1 189/2 514) evaluated by weight. The multivariate logistic regression analysis showed that higher weight growth velocity after regaining birth weight and higher cumulative calorie intake during the first week of hospitalization were protective factors against EUGR (P<0.05), while small-for-gestational-age birth, prolonged time to the initiation of total enteral feeding, prolonged cumulative fasting time, lower breast milk intake before starting human milk fortifiers, prolonged time to the initiation of full fortified feeding, and moderate-to-severe bronchopulmonary dysplasia were risk factors for EUGR (P<0.05). Conclusions It is crucial to reduce the incidence of EUGR by achieving total enteral feeding as early as possible, strengthening breastfeeding, increasing calorie intake in the first week after birth, improving the velocity of weight gain, and preventing moderate-severe bronchopulmonary dysplasia in VPIs.