Figure 1.

Third trimester-associated diabetogenically beneficial gut microbiota. As pregnancy advances, hormonal and immunological changes increase nutrient and energy harvest from the gut. These changes are induced by increased oestrogen and progesterone that inhibit gastrointestinal contractility and prolong transit providing a suitable environment (substrates) for energy-harvesting microbes. The consequent dysbiosis triggers a low-grade inflammatory state propagated by pro-inflammatory chemocytokines leading to insulin resistance and hyperglycaemia. This diabetogenic phenotype preferentially supplies abundant nutrients to the maturing foetus and prepares the mother for energy-demanding processes of parturition and lactation through the accumulation of fat and weight gain. There are also possibilities of adiposity-induced increased leptin and perhaps leptin resistance as seen in obesity. Though these are typical features of metabolic syndrome, they are not usually detrimental to maternal and fetal health in the later stage of gestation. Created with Biorender.com.