Probiotics and dietary fibre fermented milk supplementation initiated in the first trimester to prevent gestational diabetes mellitus in overweight and obese pregnant women: A randomized controlled trial.

Aims: To evaluate the effects of intensive dietary and lifestyle (IDL) interventions and probiotic and dietary fibre fermented milk (PFM) supplementation, initiated in the first trimester, on the risk of gestational diabetes mellitus (GDM) and pregnancy outcomes in overweight and obese women.

Materials and methods: In this parallel randomized controlled trial, 478 women with a prepregnancy body mass index ≥25 kg/m², enrolled at 6-12⁺⁶ weeks of gestation, were randomly assigned to IDL, PFM, or standard care (SC) groups. The primary outcome was GDM; secondary outcomes included maternal weight changes, pregnancy outcomes, and gut microbiota profiles assessed by 16S rRNA sequencing.

Results: GDM incidence was 25.60% in the IDL group (32/125), 18.42% in the PFM group (21/114), and 33.33% in the SC group (39/117) (p = 0.035). PFM reduced GDM risk by 55% compared with SC (OR = 0.45, 95% CI: 0.25-0.83). At the time of the oral glucose tolerance test (OGTT), median weight gain was lower in the IDL group (4.00 kg) than in the PFM (5.20 kg) and SC (5.65 kg) groups (p = 0.009). Correlation analysis revealed that Acidovorax abundance in PFM was negatively associated with OGTT 0 h glucose, while Megasphaera in the SC group was positively correlated with 2-hour post-load glucose (p < 0.05).

Conclusions: PFM supplementation initiated in the first trimester reduced GDM incidence. IDL reduced weight gain but had no significant effect on GDM. PFM may be a promising strategy for GDM prevention in these high-risk populations.