Effects of probiotic supplements on insulin resistance in gestational diabetes mellitus: A double‐blind randomized controlled trial

Double-blind randomized controlled trial in pregnant Thai women with diet-controlled gestational diabetes mellitus between 24 and 28 weeks of gestation, conducted at Ramathibodi Hospital in Bangkok, Thailand. The probiotic arm included 28 women based on the reported baseline activity counts; standard prenatal care was provided alongside the assigned supplement.

Pregnant women with diet-controlled gestational diabetes mellitus received one oral capsule daily of a probiotic product (Infloran®) containing Lactobacillus acidophilus 1000 million CFU and Bifidobacterium bifidum 1000 million CFU for 4 consecutive weeks after the morning meal, compared with placebo. Capsules were refrigerated at 4°C and adherence was monitored by capsule count.

Probiotic supplementation for 4 weeks improved markers of glucose metabolism without reported adverse effects. In the probiotic group, fasting plasma glucose, fasting insulin, and HOMA-IR changed less than placebo, with between-group mean differences of -3.94 mg/dL (95% CI -7.62, -0.27; p=0.03), -2.67 mIU/L (95% CI -3.57, -1.76; p=0.01), and -0.63 (95% CI -0.86, -0.41; p=0.01), respectively. Weight gain did not differ significantly between groups (MD -0.06 kg; p=0.78). The authors concluded that probiotics may be a safe adjunctive treatment for glycemic control in women with GDM.

The trial was short, lasting only 4 weeks, so long-term maternal and neonatal effects were not assessed. Generalizability is limited by the single-center Thai GDM population, and the active arm sample appears modest. Outcomes were focused on surrogate glycemic markers, with limited power to detect differences in clinical pregnancy or neonatal endpoints.