Emerging evidence about the human microbiome, a collective term for all the microorganisms living in and on the human body, consistently demonstrates the critical influence it has on host physiology and disease risk. The microbiota in the gastrointestinal (GI) tract has the most significant and far-reaching effect on human physiology. The maternal GI microbiota can decrease the risk of adverse pregnancy outcomes by modulating energy extraction, glucose metabolism, vitamin production, and host immunity essential for optimal maternal and neonatal health. Moreover, the maternal GI microbiota is thought to influence colonization of the fetus and neonate that may predispose them to different health trajectories. This article provides a basic understanding about the influence of the structure of the maternal GI microbiota, the fundamental role it plays during pregnancy, and the factors that influence the structure, and subsequently function, of the GI microbiota in the general and pregnant population. While only a small number of studies have examined this topic during pregnancy, the preponderance of the evidence supports the need to clarify baseline structure and function of GI microbiota and its associations with pregnancy outcomes. In addition, the results from the studies conducted in the general population can be extrapolated to pregnancy in many cases. This knowledge is essential for clinicians who need to understand the implications of the microbiota for disease and wellness in order to address the care factors that may adversely influence the GI microbiota during pregnancy.
Keywords: gastrointestinal microbiota; microbiome; pregnancy.