目的 阐明妊娠期糖尿病（GDM）患者合并B族链球菌（GBS）感染的临床特点以及对妊娠结局的影响，分析糖化血红蛋白（HbA_1c）、中性粒细胞与淋巴细胞比值（NLR）、血小板与淋巴细胞比值（PLR）在GDM患者合并GBS感染及其并发症绒毛膜羊膜炎的预测价值。 方法 回顾性选取2023年1月至2024年12月佛山市南海区妇幼保健院收治的277例诊断为GDM的住院孕妇，其中GDM患者合并GBS感染为阳性组（n = 75）；GDM患者未合并GBS感染为对照组（n = 202）。比较两组孕妇在年龄等临床资料和妊娠结局的区别，采用多因素logistic回归分析，探讨GDM患者发生GBS感染的危险因素，以及GDM合并GBS感染者发生绒毛膜羊膜炎的危险因素；并采用受试者工作（ROC）曲线评估相关指标的预测价值。 结果 阳性组的HbA_1c、NLR、PLR水平显著升高，胎膜早破及宫内窘迫的发生率亦明显增加，差异有统计学意义（均P < 0.05）。多因素logistic回归分析结果显示，HbA_1c（OR = 2.574， 95% CI： 1.355 ~ 4.889）、NLR（OR = 1.545， 95% CI： 1.318 ~ 1.811）是GDM患者发生GBS感染的独立危险因素（均P < 0.05）。同时，NLR（OR = 1.694， 95%CI： 1.242 ~ 2.190）是合并GBS感染的GDM患者发生绒毛膜羊膜炎的独立危险因素。ROC曲线结果显示，基于NLR和HbA_1c构建的联合预测模型，预测GDM患者发生GBS感染的曲线下面积（AUC）为0.800（95%CI： 0.741 ~ 0.859），NLR预测绒毛膜羊膜炎的AUC为0.855（95%CI： 0.760 ~ 0.951）。PLR与GBS感染及其并发症无显著相关性（P > 0.05）。 结论 GDM患者合并GBS感染会增加孕妇不良妊娠结局的风险，较高水平的HbA_1c、NLR是GDM患者发生GBS感染的独立危险因素，NLR对GDM合并GBS感染者发生绒毛膜羊膜炎有预测价值。建议加强高危妊娠管理，避免不良妊娠结果和降低围产期母婴感染的几率。

Objective To clarify the clinical characteristics of patients with gestational diabetes mellitus （GDM） complicated by group B streptococcus （GBS） infection and its impact on pregnancy outcomes， and to analyze the predictive value of glycated hemoglobin （HbA_1c）， neutrophil-to-lymphocyte ratio （NLR）， and platelet-to-lymphocyte ratio （PLR） in GDM patients complicated by GBS infection and its complication， chorioamnionitis. Methods A retrospective selection was conducted on 277 inpatients diagnosed with GDM who were admitted to the NanhaiMaternal and Child Health Hospital， Foshan City from January 2023 to December 2024. Among these patients， those with GDM combined with GBS infection were assigned to the positive group （n = 75）， while those with GDM but without GBS infection were assigned to the control group （n = 202）. The differences in clinical data， including age， and pregnancy outcomes between the two groups of pregnant women were compared. Multivariate logistic regression analysis was employed to explore the risk factors for GBS infection in GDM patients and the risk factors for chorioamnionitis in GDM patients with GBS infection. The predictive value of the relevant indicators was assessed using the receiver operating characteristic curve （ROC）. Results In the positive group， the levels of HbA_1c， NLR， and PLR were significantly elevated. Moreover， the incidences of premature rupture of membranes and intrauterine distress also showed a significant increase， and these differences were statistically significant （all P < 0.05）. The results of multivariate logistic regression analysis indicated that HbA1c （OR = 2.574， 95%CI： 1.355 ~ 4.889） and NLR （OR = 1.545， 95%CI： 1.318 ~ 1.811） were independent risk factors for GBS infection in patients with GDM （all P < 0.05）. Meanwhile， NLR （OR = 1.694， 95%CI： 1.242 ~ 2.190） was identified as an independent risk factor for chorioamnionitis in GDM patients with GBS infection. The ROC curve results demonstrated that the area under the curve （AUC） of the combined prediction model constructed based on HbA_1c and NLR for predicting GBS infection in GDM patients was 0.800 （95%CI： 0.741 ~ 0.859）， and the AUC of NLR for predicting chorioamnionitis was 0.855 （95%CI： 0.760 ~ 0.951）. The PLR had no significant correlation with GBS infection and its complications （P > 0.05）. Conclusions GBS infection in patients with GDM elevates the risk of adverse pregnancy outcomes among pregnant women. Elevated levels of glycated HbA_1c and NLR are independent risk factors for GBS infection in GDM patients. The NLR holds predictive value for chorioamnionitis in GDM patients with GBS infection. It is advisable to enhance the management of high-risk pregnancies to prevent adverse pregnancy outcomes and mitigate the risk of maternal and infant infections during the perinatal period.