The Influence of Snacking on Glycaemia in Women With Gestational Diabetes Mellitus: A Systematic Review.

Gestational diabetes mellitus (GDM) is characterised by glucose intolerance identified during pregnancy, typically resolving postpartum. Globally, the standardised prevalence is 14%. Dietary management is essential in mitigating adverse maternal and infant outcomes, with guidelines recommending low- or no-carbohydrate snacks to stabilise blood glucose concentrations. However, the influence of snacking patterns on glycaemic outcomes in women with GDM has yet to be assessed by systematic review. Following PRISMA guidelines, this review examines the association between snacking patterns, specifically timing, frequency, and composition, and glycaemia in this population. Electronic searches were conducted in MEDLINE, Embase, Maternity and Infant Care (MIDIRS), and CINAHL in April 2024, with an updated search performed in June 2025. Reference lists and citations were also screened. Studies examining the impact of snacking on glycaemia in women with GDM were included. Of the 7405 articles identified, five studies met the inclusion criteria: four 1-8-week intervention studies and one 7-day observational study. The included studies showed considerable heterogeneity in their designs. Evidence for a relationship between snacking and glycaemia in GDM was mixed, with some studies suggesting glycaemic benefits from snacking, including bedtime snacking, while others found that bedtime snacks adversely influenced glycaemia. Any association between snacking and glycaemia in individuals with GDM remains inconclusive due to limited available data, study heterogeneity, and conflicting results. The lack of high-quality studies underscores the need for further research to define the role of snacking in glycaemia among this population.