Background: Current management for gestational diabetes (GDM) includes dietary and physical activity advice, blood glucose monitoring and often insulin therapy. The primary aim of dietary advice is to stabilise maternal blood glucose levels after meals through carbohydrate modification. However, evidence from randomised controlled trials demonstrates that these dietary strategies do not consistently support improvements in maternal and infant health. Maternal plasma triglycerides are also significant predictors of GDM, and they strongly associate with infant adiposity. Importantly, triglycerides can be modified through different dietary strategies.
Objective: To assess the feasibility of a low-intensity dietary intervention designed to lower triglycerides within the current model of care for GDM management.
Methods: Women with GDM were randomised at ~30 weeks’ gestation to usual care (Control) group or an Intervention group, at an allocation ratio of 1:1. The Control group received standard dietary advice for GDM. The Intervention group received standard care plus individual counselling on how to decrease consumption of ultra-processed foods, increase intakes of fruits, vegetables, fish and nuts, and changes to healthier fats. The primary outcome is study feasibility (participant recruitment and retention rates); secondary outcomes include dietary intakes and birthweight.
Results: Over 7 months of active recruitment (rate 1 person/week), 264 women were invited to participate. Of these, 40 women were eligible (15.2%), 28 (10.6%) consented and were randomised (n=15 intervention, n=13 control) and 26 women completed the study (92.9% retention rate). Compared to baseline, the Intervention group increased intakes of nuts (0.15 serves/d) and healthy fats (0.5 tsp/d) whereas the Control group reported no change. Dietary intakes of sugar and saturated fat decreased in the Intervention group by a respective 9 g/d and 1 g/d, whereas in the Control group, intakes increased (4 g/d; 2.5 g/d). The mean (±SE) birthweight was lower in the Intervention vs Control group (3016± 173 g vs. 3542 ±174 g, P=0.048).
Conclusions: There was a modest recruitment rate and a high retention rate, indicating a triglyceride lowering diet in women with GDM is feasible and highly acceptable. The positive improvements observed in maternal nutritional intake and desirable birthweight warrants further investigation in a larger, definitive, randomized controlled trial.