Childhood obesity has reached epidemic levels worldwide and represents a major public health challenge with a high economic burden associated with its treatment. According to the World Health Organization (WHO), around 39 million children under 5 years old were overweight or obese in 2020. The causes are complex and multifactorial and involve the interaction between genetics, environmental and developmental factors, and the gut microbiota. However, it is estimated that only about 20% of obesity risk is of genetic origin. The Developmental Origins of Health and Disease hypothesis states that the intrauterine environment influences fetal development and future disease susceptibility. One of the mechanisms by which in utero exposures may induce metabolic alterations is through epigenetic alterations that in turn are influenced by environmental factors related to the mother during pregnancy such as nutrition, physical activity, or toxic habits.