Oral Presentation Australasian Diabetes in Pregnancy Society Conference 2026

The maternal-fetal and health economic impact of a resistant starch dietary intervention in Gestational Diabetes (139159)

Cathy Latino 1 2 3 , Johnny Lo 4 , Emily Gianatti 5 , Marshall Makate 6 , Amanda Devine 2 3 , Claus Christophersen 2 3 7
  1. Department of Dietetics, Fiona Stanley Hospital, Murdoch, WA, Australia
  2. School of Medical & Health Sciences, Edith Cowan University, Joondalup, WA, Australia
  3. Nutrition and Health Innovation Research Institute, Edith Cowan University, Joondalup, WA, Australia
  4. School of Science, Edith Cowan University, Joondalup, WA, Australia
  5. Department of Endocrinology, Fiona Stanley Hospital, Murdoch, WA, Australia
  6. School of Population Health, Curtin University, Bentley, Western Australia, Australia
  7. WA Human Microbiome Collaboration Centre, Curtin University, Bentley, WA, Australia

Background: Fermentable dietary fibres such as resistant starch (RS) influence glycaemic control through modulation of the gut microbiota, enhanced short-chain fatty acid production, and improved insulin sensitivity. In gestational diabetes mellitus (GDM), where gut dysbiosis, metabolic dysregulation, and healthcare utilisation are elevated, the potential clinical and health economic benefits of RS-focused dietary strategies remain largely unexplored.

Aim: To evaluate the effects of increased dietary RS intake on fasting glycaemia, maternal-fetal outcomes, and health service costs in women with GDM.

Methods: Women newly diagnosed with GDM between 24-30 weeks’ gestation were block‑randomised by pre‑pregnancy BMI to one of three diets from diagnosis until delivery: standard care (Control), high‑RS diet (RS-Diet), or high‑RS diet plus RS supplement (RS-Supp). Fasting blood glucose (FBG), 3-day food diaries, gastrointestinal symptoms, and maternal-fetal outcomes were collected. Direct hospital costs, including antenatal outpatient care, maternal inpatient services, and neonatal intensive care unit (NICU) costs, were sourced from Activity Based Funding records. Statistical analyses included mixed modelling and logistic regression.

Results: Sixty-nine women were enrolled (n=23/group). RS, fibre, and carbohydrate intakes increased significantly in both intervention groups without worsening gastrointestinal symptoms. Mixed modelling showed a trend toward an inverse association between RS intake and FBG at one week (r=-0.175, p=0.051), although no between-group differences in FBG were observed. NICU admissions were substantially lower in the intervention groups (n=2 each) compared with Controls (n=8) (Odds Ratio=0.19, p=0.034). Neonatal anthropometry and maternal insulin use were similar across groups. Reduced NICU utilisation translated to markedly lower NICU-related costs in RS-Diet (AUD 10,084) and RS-Supp (AUD 25,451) compared with Controls (AUD 50,317). Net monetary benefits were AUD 46,326 (RS-Diet) and AUD 45,586 (RS-Supp). Other antenatal and maternal inpatient costs did not differ.

Conclusion: Increasing dietary RS intake in GDM is feasible, well-tolerated, and associated with fewer NICU admissions, resulting in meaningful cost savings. While based on a modest sample, these findings indicate a potentially important signal for maternal-fetal care and service utilisation. Larger trials are needed to confirm these effects and define their clinical implications. Mechanistic analyses of maternal and neonatal microbiota, metabolomics, and lipid profiles will also be presented.