Changes in Microbiome during the gestation period

When studying the role of the microbiota in pregnancy, it is crucial to consider the stage at which the essential interaction between the host and its microbes begins. The gut microbiota changes dramatically during pregnancy. The gut microbiota during pregnancy is influenced not only by internal cues, but also by environmental factors, primarily by diet. The maternal microbiome has emerged as an important factor in gestational health and outcome and is associated with risk of preterm birth and fetuses morbidity. Microbial me- tabolites, e.g. short-chain fatty acids affect gut-brain signaling and the immune response. Pregnancy is shown to alter the maternal gut microbiota. Recent studies have suggested that changes to the microbiota during pregnancy may influence these pregnancy-associated metabolic changes. The vaginal microbiome becomes dominated by Lactobacilli species during pregnancy. Bacterial infections during pregnancy can be caused by a single species of bacteria, by an imbalance in the microbiomes, or by gut dissemination of bacteria. In pregnancy dramatical changes of the maternal microbiota affects neonatal immune responses and maturation the design product. Clinically, abnormal changes in the vaginal microbiome have been associated with pre- term birth. It is, therefore, not surprising that there are also significant changes in the micro- biome during pregnancy when there is an excess of weight with metabolic and immunolo- gical changes occur. We believe that the microbial alterations observed during pregnancy are vital for a healthy pregnancy. In this review, I summarize the known changes in microbial composition througho- ut pregnancy in the gut, vagina, oral cavity and placenta.