Early exposures to biological, chemical, or social stress can have a long-term impact on adult health. However, the processes underlying these developmental origins of health and disease (DOHaD) are not fully understood. Epigenetic mechanisms govern the determination of cellular identity during organ differentiation. This developmental plasticity gives them a particular sensitivity to the environment. They are therefore good candidates to explain how early events can modify physiology until adulthood. Male offspring of obese mouse mothers have a higher risk of having low birth weight and developing obesity. In addition, the expression of genes encoding epigenetic modifiers is altered in the placenta and fetal liver. The offspring of mothers who lost weight before gestation, due to a nutritional intervention, do not present phenotypic abnormalities, but gene expression is not normalized. This suggests that deleterious phenotypes could appear with aging. Thus, epigenetic mechanisms are particularly sensitive to maternal nutrition and energy metabolism in utero, which opens up new avenues of research.