Obesity and Its Role in Fetal Programming—A Narrative Review

The prevalence of maternal obesity is rapidly increasing, which represents a major public health concern worldwide. Currently more than 50% of all adult women are overweight or obese, and this trend is reflected in women of child-bearing age. Maternal obesity is characterized by metabolic dysfunction and chronic inflammation, and is associated with health problems in both the mother and the offspring. Intrauterine programming occurs during embryonic and fetal development, a critical period not only for the formation of tissues and organs but also for the etiology of diseases later in life. The principal mechanisms underlying fetal programming in the offspring of obese mothers appear to involve DNA methylation and chromatin remodeling within progenitor cells. Aberrant DNA methylation patterns have been identified in genes involved in insulin signaling, lipid metabolism, and appetite regulation in the placenta and fetal tissues. Histone modifications, such as acetylation and methylation of histone tails, may also play a crucial role in modulating chromatin structure and accessibility of transcriptional machinery to DNA. The persistence of such modifications throughout life, and potentially across generations, can lead to permanent alterations in gene expression, thereby contributing to the intergenerational transmission of metabolic disorders. The aim of this paper is to present an overview of the current knowledge regarding the effects of maternal obesity on fetal development and the occurrence of fetal complications, as well as long-term complications observed in adulthood related to intrauterine exposure to maternal obesity, including hypertension and cardiovascular diseases, impaired insulin secretion and resistance, diabetes mellitus, and metabolic syndrome. The mechanisms underlying fetal programming are also discussed.