Effect of Medical Nutrition Therapy on glycemic control and adverse pregnancy outcomes with Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

Abstract

Objective: Medical nutrition therapy (MNT) and conventional dietary intervention were compared in this study to determine their respective impacts on glycemic regulation and the incidence of adverse pregnancy outcomes (APOs) in  gestational diabetes mellitus (GDM). Methods: Through a systematic search of PubMed, Embase, Cochrane databases, Web of Science, as well as the Chinese Biomedical Literature Database (SinoMed), China National Knowledge Infrastructure (CNKI), Wanfang Data, and VIP databases, eligible randomized controlled trials (RCTs) comparing MNT with conventional dietary control were identified. The retrieval window included all records available since the establishment of the respective databases, with the final search date being September 6, 2025. Blood glucose control was studied by comparing glycated hemoglobin (HbA1c), fasting blood glucose (FBG), two-hour postprandial blood glucose (2hPBG) and fasting plasma glucose (FPG). The occurrence rate of APOs was investigated using comparative evidence on complications affecting mothers and neonates. Meta-analysis served as the analytical method, and either random-effects or fixed-effects modeling was used. Results: The meta-analysis incorporated 15 RCTs that enrolled a total of 1,479 patients with GDM. Relative to usual dietary control, MNT was linked to significant declines in HbA1c (MD = -0.99; 95% CI, -1.44 to -0.55; P < 0.00001), FBG (MD = -0.84; 95% CI, -1.07 to -0.60; P < 0.00001),  2hPBG (MD = -1.43; 95% CI, -1.87 to -0.98; P < 0.00001) and FPG (MD = -0.54; 95% CI, -0.58 to -0.32; P < 0.00001). Furthermore, MNT was associated with substantially diminished risks for maternal complications (RR = 0.41; 95% CI, 0.32 to 0.54) and neonatal complications (RR = 0.34; 95% CI, 0.26 to 0.44). Across the included studies, no serious adverse events that could be attributed to MNT were documented. Conclusion: For patients with GDM, the use of MNT during pregnancy is capable of improving blood sugar regulation and decreasing the risk of complications among mothers and neonates. For GDM management, MNT should be emphasized as a safe and effective non-pharmacological intervention measure. Further confirmation of its long-term effects requires additional RCTs with stronger study quality.