Summary: The prenatal period is increasingly recognized as a critical window for metabolic and immunological programming, shaping long-term health trajectories from childhood into adulthood. According to the Developmental Origins of Health and Disease (DOHaD) framework, maternal nutrition, environmental exposures, and psychosocial stressors during pregnancy can induce lasting epigenetic, structural, and physiological changes in the offspring. These alterations increase the risk of chronic diseases, including obesity, type 2 diabetes, hypertension, and neurodevelopmental disorders. Nutritional deficiencies, maternal undernutrition, and restrictive eating behaviors related to famine, religious fasting, or inadequate dietary choices have been associated with impaired fetal growth, reduced nephron number, altered stress axis regulation, and elevated cardiometabolic risk later in life. Conversely, excessive maternal weight gain and high-fat dietary patterns predispose children to early insulin resistance, adiposity, and adverse endothelial function. Essential micronutrients such as folic acid, vitamin D, vitamin B12, iodine, calcium, and iron remain central to fetal development, and their supplementation should be an integral part of pediatric care. Recent evidence also highlights the importance of maternal gut microbiota in shaping infant immune competence and metabolic resilience. Probiotic supplementation with strains such as Lactobacillus rhamnosus or Bifidobacterium lactis may reduce the incidence of atopic disease and metabolic dysregulation, although clinical use requires careful evaluation due to potential risks such as gestational hypertension. For pediatricians and family physicians, awareness of these mechanisms is crucial. As first-line contacts for pregnant women and parents, they play a pivotal role in providing evidence-based dietary guidance, ensuring appropriate supplementation, and supporting preventive strategies that extend beyond pregnancy, fostering healthier outcomes for future generations.