目的 基于中国人群体重指数（BMI）分类方法及中国营养学会最新推荐的孕期增重范围，评估妊娠妇女孕前BMI和孕期增重现状，并探讨其对新生儿出生结局的影响。方法 纳入2018年1月至2019年12月建档并定期随访产检的孕妇26 422例，描述研究对象孕前BMI和孕期增重及其亚组间人口学特征，采用单因素及多因素二分类logistic回归分析两者与多种新生儿结局（如巨大儿、低出生体重、早产、窒息）间的关系。最后通过热图探索孕前BMI和孕期增重对胎儿体重的综合影响。结果 研究发现低体重孕妇和超重肥胖孕妇占比相似，分别为13.8%和14.7%；超过50%的孕妇孕期增重异常。孕期增重不足增加早产风险；孕前BMI过低或孕期增重不足增加小于胎龄儿（SGA）风险，而孕前BMI过高或孕期增重过多增加大于胎龄儿（LGA）及难产（剖宫产、产钳/胎吸）风险（P<0.05）。多因素分析未发现孕前BMI及孕期增重与新生儿窒息间的关系（P>0.05）。结论 妊娠妇女孕期增重异常问题仍较突出，提示产科医护人员及社会需加强对孕妇孕期知识的普及和体重管理。临床工作中可利用热图评估个体发生异常胎儿体重及难产的风险，以降低不良结局。

Objective Based on the body mass index (BMI) classification of Chinese population and the latest recommended range of gestational weight gain by the Chinese Nutrition Society, this study aims to evaluate the pre-pregnancy BMI and gestational weight gain status of pregnant women and further explored explore their influence on neonatal birth outcomes. Methods A total of 26 422 pregnant women who received regular prenatal examination were selected from January 2018 to December 2019 were included. The pre-pregnancy BMI, gestational weight gain of the study subjects, and their demographic characteristics among subgroups were described. Univariate and multivariate binary logistic regression analyses were employed to investigate the relationships between pre-pregnancy BMI and gestational weight gain and various neonatal outcomes (such as macrosomia, low birth weight, preterm birth, and asphyxia). Finally, a heatmap was utilized to explore the combined effect of pre-pregnancy BMI and gestational weight gain on fetal weight. Result The study found that the proportions of underweight and overweight/obese pregnant women were 13.8% and 14.7%, respectively, indicating a similar distribution. More than 50% of the participants experienced abnormal gestational weight gain. Insufficient gestational weight gain was associated with an increased risk of preterm birth. A low pre-pregnancy BMI or insufficient gestational weight gain elevated the risk of small for gestational age (SGA), whereas a high pre-pregnancy BMI or excessive gestational weight gain increased the risk of large for gestational age (LGA) and dystocia (cesarean section, forceps/vacuum extraction) (P<0.05). Multivariate analysis did not reveal a significant association between pre-pregnancy BMI, gestational weight gain, and neonatal asphyxia (P>0.05). Conclusion Abnormal gestational weight gain remains a significant issue among pregnant women, suggesting that obstetric healthcare providers and society need to strengthen the dissemination of pregnancy knowledge and weight management for pregnant women. In clinical practice, heatmaps can be utilized to assess individual risks of abnormal fetal weight and dystocia, thereby reducing adverse outcomes.