Prevention of Type 2 Diabetes after Gestational Diabetes Mellitus: A Systematic Review and Meta-analysis of Lifestyle and Pharmacological Interventions Protocol

Abstract 1. Background: A significant increase in the reported prevalence of gestational diabetes mellitus (GDM) has been observed. While most affected women regain normal glucose tolerance postpartum, approximately 35–60% remain at risk of developing diabetes after pregnancy (DAP) within 10–20 years. This review focuses on long-term maternal metabolic outcomes and the continuous management of GDM to prevent or delay progression to overt postpartum diabetes. 2. Objectives: Although landmark studies have demonstrated the efficacy of cornerstone interventions—insulin, metformin, and dietary therapy—comparative evidence to guide the selection of these strategies over another in specified circumstances remains limited. The objective of this protocol is to ascertain optimal therapeutic approaches for women with GDM during pregnancy and the postpartum period. 3. Methods: A comprehensive search strategy is employed using PubMed, Embase, Web of Science, Scopus, and ClinicalTrials.gov. Diabetes-focused journals and reference lists of relevant publications were also reviewed. The search includes studies published from 2000 onward. Two authors independently perform screening studies, extracting data and assessing risk of bias using Cochrane RoB 2.0 and a combination of the Newcastle–Ottawa Scale and ROBINS-I. The certainty of evidence is evaluated using GRADE. Given anticipated heterogeneity, findings will be synthesized narratively and stratified by study design. 4. Conclusions: This protocol outlines a systematic review designed to determine whether selective use of treatments during pregnancy and after delivery influences long-term risk of type 2 diabetes mellitus, with the goal of comparing postpartum prevention strategies. 5. Registration: This study protocol was developed in accordance with PRISMA-P guidance, fully registered in Zenodo and PROSPERO (ID: CRD420251039675). It is not an update of a previous protocol and has not undergone peer review.