Glucose monitoring based on habitual dietary intake as an alternative screening test for diagnosing gestational diabetes mellitus: a systematic review

INTRODUCTION: Early detection of gestational diabetes mellitus (GDM) is crucial for timely treatment to prevent maternal and neonatal complications. The oral glucose tolerance test (OGTT) is considered the gold standard for GDM screening, however, it is burdensome and involves a supra-physiological glucose load. This systematic review assesses the sensitivity and specificity of a glucose-monitoring curve in pregnant women using their habitual diet as an alternative screening method. METHODS: Embase, MEDLINE, Web of Science Core Collection and Cochrane Central Register of Trials were systematically searched. Studies investigating at least the pre- and postprandial glucose curve as a screening method for GDM were included. Quality was assessed using the QUADAS tool. RESULTS: Out of 3988 screened articles, six met the inclusion criteria, comprising 1,699 women at risk for GDM. A glucose-monitoring curve based on usual dietary intake demonstrated a sensitivity between 22 and 80% and a specificity between 68 and 98%. These values were observed in comparison to the OGTT and the presence of pregnancy-related complications or a consensus-based diagnostic standard. Due to heterogeneity in study design and outcome measures, meta-analysis was not feasible. CONCLUSION: This systematic review indicates that glucose monitoring based on a woman’s habitual dietary intake shows potential as an alternative diagnostic approach for GDM. However, sensitivity and specificity varied widely across studies, reflecting heterogeneity. Nonetheless, habitual-diet glucose monitoring appears to be a promising, more physiologically representative alternative to the conventional OGTT. Given the limitations and potential diagnostic inaccuracies of the OGTT, further research is warranted to validate this method and support its integration into standardized GDM screening protocols. TRIAL REGISTRATION: International Prospective Register of Systematic Reviews (PROSPERO) Identifier: CRD42024612929.