本期刊发的刘晓阳等作者撰写的《足月妊娠孕周与不良围产结局的相关性分析：一项基于43 502 名中国孕产妇的回顾性队列研究》一文，以基于四川大学华西第二医院13 123例单胎足月、自然分娩产妇的临床数据为基础，系统分析了37⁺⁰~41⁺⁶周内不同分娩时机对新生儿结局的影响，并指出39⁺⁰~40⁺⁶周为不良结局风险较低的“窗口期”。本研究思路明确、统计方法先进，尤其在处理孕周与结局的非线性关系上采用了限制性立方样条模型，具有较高的临床参考价值。然而，作为一项回顾性研究，其在因果推断、混杂控制与外推性方面也存在一定的局限性。本文结合对该研究报告的点评，就回顾性研究的价值和局限作出概要分析。

The article of "The association of gestational age at term and adverse perinatal outcomes: a retrospective study based on 43502 Chinese pregnant women" by Liu Xiaoyang and co-authors published in this issue, was based on the clinical data of 13,123 singleton full-term and natural delivery mothers from West China Second University Hospital of Sichuan University. It systematically analyzed the impact of different delivery timings within 37⁺⁰ to 41⁺⁶ weeks on neonatal outcomes, and pointed out that 39⁺⁰ to 40⁺⁶ weeks is a "window period" with a relatively low risk of adverse outcomes. This study had a clear research idea and advanced statistical methods, especially in handling the non-linear relationship between gestational age and outcomes, it adopted the restricted cubic spline model, which had high clinical reference value. However, as a retrospective study, it also had certain limitations in causal inference, confounding control, and generalizability. This article, in combination with the review of this research report, makes a summary analysis of the value and limitations of retrospective studies.