Metformin is an effective oral hypoglycaemic agent used in the treatment of type 2 diabetes mellitus; however, its use in pregnancy for the treatment of gestational diabetes mellitus (GDM) remains controversial owing to concerns around safety and efficacy. This comprehensive review outlines the physiological metabolic functions of metformin and synthesizes existing literature and key knowledge gaps pertaining to the use of metformin in pregnancy across various end points in women with GDM. On the basis of current evidence, metformin reduces gestational weight gain, neonatal hypoglycaemia and macrosomia and increases insulin sensitivity. However, considerable heterogeneity between existing studies and the grouping of aggregate and often inharmonious data within meta-analyses has led to disparate findings regarding the efficacy of metformin in treating hyperglycaemia in GDM. Innovative analytical approaches with stratification by individual-level characteristics (for example, obesity, ethnicity, GDM severity and so on) and treatment regimens (diagnostic criteria, treatment timing and follow-up duration) are needed to establish efficacy across a range of end points and to identify which, if any, subgroups might benefit from metformin treatment during pregnancy.

二甲双胍是一种有效的口服降糖药，用于治疗 2 型糖尿病;然而，由于对安全性和有效性的担忧，其在妊娠期用于治疗妊娠糖尿病 （GDM） 仍存在争议。本综述概述了二甲双胍的生理代谢功能，并综合了与 GDM 女性妊娠期使用二甲双胍有关的现有文献和关键知识空白。根据目前的证据，二甲双胍可减少妊娠期体重增加、新生儿低血糖和巨大儿，并增加胰岛素敏感性。然而，现有研究之间的相当大的异质性以及荟萃分析中汇总且通常不和谐的数据分组导致关于二甲双胍治疗 GDM 高血糖的疗效存在不同的结果。需要创新的分析方法，根据个体水平特征（例如，肥胖、种族、GDM 严重程度等）和治疗方案（诊断标准、治疗时间和随访持续时间）进行分层，以确定一系列终点的疗效，并确定哪些亚组（如果有）可能从怀孕期间的二甲双胍治疗中受益。