**4. Probiotic interventions to ameliorate gestational diabetes**

Most of RCTs investigating the therapeutic benefits of probiotic supplementation in female GDM patients have been carried out in Iran; each study used a unique combination of microorganisms and examined a variety of outcomes in addition to glycemia such as gestational weight change [104], lipid profile [105], and inflammation [106]. Fasting blood sugar levels and insulin resistance dramatically decreased in the probiotic group in all these studies. Probiotics also decreased gestational weight

**Figure 4.** *Potential mechanisms of probiotics against gestational diabetes.*


### **Table 5.**

*Overview of important studies demonstrating the effect of probiotics on human subjects with gestational diabetes.*

gain, serum very-low-density lipoprotein (VLDL) cholesterol, and triglyceride levels [104–106]. **Figure 4** shows an overview of potential mechanisms of probiotics against type 1 diabetes.

A recent study that randomly assigned GDM patients to receive probiotics (109 colony-forming units (CFU) per day of *Bifidobacterium bifidum* and *Lactobacillus acidophilus* or a placebo for four weeks also found significant improvement in glucose metabolism in the probiotic group, including fasting glucose, insulin, and HOMA-IR. An RCT conducted in Ireland randomized 149 women (GDM sufferers) to receive either a probiotic (*Lactobacillus salivarius*, 109 CFU per day) or a placebo, and the results showed no change between the two groups except for total cholesterol [107]. There was a considerable decrease in insulin resistance, which seemed to be primarily related to the species *Bifidobacterium* [108]. According to the findings, bigger, longerterm studies comparing various probiotic strains were required.

A modest number of RCTs have looked at probiotic supplementation's potential to stop GDM. In the Finnish "Probiotics and Pregnancy Outcome Study, " pregnant women were randomly assigned to receive dietary advice with probiotic supplementation (1010 CFU per day of *Lactobacillus rhamnosus* and *Bifidobacterium lactis*), dietary advice alone, or a placebo. In the probiotic group, the rate of GDM was much lower as compared to the other groups. There were no abnormalities in fetal development [109]. **Table 5** provides an overview of important studies demonstrating the effect of probiotics on human subjects with gestational diabetes. Recently, a probiotic intervention study for women at risk of GDM in New Zealand has been carried out. At 14–16 weeks of gestation, the scientists randomly assigned women to take either a probiotic (*Lactobacillus rhamnosus*, 6 × 109 CFU per day) or a placebo. They also noticed that the probiotic intervention dramatically reduced the occurrence of GDM [110]. Even though the results are encouraging, further research is required to decide if probiotic supplements should be widely utilized in early pregnancy to prevent GDM.
