目的 探讨超低出生体重儿（extremely low birth weight infant, ELBWI）在出生后前2周的液体平衡状态与临床危重并发症之间的关系，旨在减少液体超载对不良预后的影响。 方法 回顾性分析2019年1月—2024年12月南京医科大学附属妇产医院新生儿重症监护病房住院的226例ELBWI的临床资料。将发生重度支气管肺发育不良（severe bronchopulmonary dysplasia, sBPD）或死亡者列为危重并发症组（99例），存活且仅发生中度及以下BPD者为对照组（127例）。通过出生体重变化百分比定义液体平衡指标。评估ELBWI出生后前2周液体超载与ELBWI发生sBPD或死亡之间的关系。 结果 单因素分析显示，生后第3天、第7天、第10天、第14天的液体平衡状态，以及前3 d体重下降低于3%、前7 d体重下降低于6%，与危重并发症发生显著相关（均P<0.05）。控制混杂因素后进行多因素logistic回归分析，结果显示，生后第3天、第7天、第10天、第14天液体超载是发生危重并发症的危险因素（OR>1，P<0.05），前3 d体重下降低于3%（OR=5.213，95%CI：2.349~11.567）、前7 d体重下降低于6%（OR=3.920，95%CI：1.806~8.511）时危重并发症发生风险显著升高。 结论 在ELBWI中，早期液体超载可能与sBPD或死亡风险相关，适度液体限制或有助于改善预后，需前瞻性研究进一步验证。

Objective To explore the relationship between fluid balance during the first 14 postnatal days and critical clinical complications in extremely low birth weight infants (ELBWIs), with the aim of reducing the impact of fluid overload on adverse outcomes. Methods Clinical data of 226 ELBWIs admitted to the neonatal intensive care unit of the Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University from January 2019 to December 2024 were retrospectively analyzed. Infants who developed severe bronchopulmonary dysplasia (sBPD) or died were classified as the critical complication group (n=99), and survivors with at most moderate BPD (none, mild, or moderate) were classified as the control group (n=127). Fluid balance indices were defined by the percentage change from birth weight. The association between fluid overload during the first 14 postnatal days and the occurrence of sBPD or death was evaluated. Results Univariate analysis showed that fluid balance on postnatal days 3, 7, 10, and 14, as well as weight loss <3% within the first 3 days and <6% within the first 7 days, was significantly associated with the occurrence of critical complications (all P<0.05). After adjustment for confounders in multivariable logistic regression, fluid overload on postnatal days 3, 7, 10, and 14 was a risk factor for critical complications (OR>1, P<0.05), and the risk of critical complications increased significantly when weight loss was <3% within the first 3 days (OR=5.213, 95%CI: 2.349-11.567) and <6% within the first 7 days (OR=3.920, 95%CI: 1.806-8.511). Conclusions In ELBWIs, early fluid overload may be associated with an increased risk of sBPD or death, and moderate fluid restriction may help improve prognosis; prospective studies are required for further validation.