A gut-brain axis (GBA) has a long history of conceptual development. Intestinal dysbiosis has now been recognized as a key player in the development of adult neurodevelopmental disorders, obesity, and inflammatory bowel disease. Recent developments in metagenomics suggest those nutrition and gut microbiotas (GM) are important regulators of the gut-brain communication pathways that cause neurodevelopmental and psychiatric problems in adulthood. Intestinal dysbiosis and neurodevelopmental disease outcomes in preterm newborns are being linked by recent research. Recent clinical investigations demonstrate that in critical care units, intestinal dysbiosis occurs before late-onset newborn sepsis and necrotizing enterocolitis. Strong epidemiologic data also shows a connection between necrotizing enterocolitis and extremely low birth weight babies' long-term psychomotor impairments and late-onset neonatal sepsis. The GBA theory suggests that intestinal bacteria may indirectly affect preterm newborns' developing brains. In this review, we emphasize the structure and function of the GBA and discuss how immune-microbial dysfunction in the gut affects the transmission of stress signals to the brain. Preterm babies who are exposed to these signals develop neurologic disorders. Understanding neuronal and humoral communication through the GBA may provide insight into therapeutic and nutritional strategies that may enhance the results of very low-birth-weight babies.