2.1.1. Maternal Risk Factors

Epidemiologic and prospective cohort studies have identified maternal and gestational conditions that confer increased risk for subsequent cardiometabolic disorders [2].

Global rates of childhood obesity have increased dramatically. Evidence suggests that exposure in utero to maternal obesity or gestational diabetes mellitus (GDM) may contribute to these alarming trends [3,4]. Children born to mothers with GDM or obesity during pregnancy have an increased likelihood of developing obesity and metabolic disorders compared with unexposed children [3,4]. It is challenging to distinguish the effects of maternal obesity and diabetes in the preconception period compared to the gestational period, as these characteristics generally track over time. Effects and associated mechanisms could differ for preconception vs. gestational exposure, resulting in a complex interaction between the effects of both periods [5]. The epidemiological evidence supports the need for preconception and early-life interventions to reduce the obesity and diabetes burden in later life [6].

The potential role of the paternal metabolic contribution to a child's later risk of disease has progressively gained more attention. Parental obesity is also a strong predictor of childhood obesity, and even more so when both parents are obese, this risk appears to be even greater [7]. Children of parents with obesity likely share not only genetic risks but also extra-uterine, environmental and lifestyle-related exposures that could explain some of the associations observed with parental preconception obesity and the offspring's obesity risk.

There is some evidence that environmental exposures during pregnancy influence fetal growth and later risk of obesity on offspring. Maternal smoking during pregnancy is associated with restricted fetal growth [2]. Additionally, in later childhood, children of these mothers have a 1.5-fold greater risk for overweight and obesity as compared to those born to mothers who did not smoke [8]. Air pollution and exposure to synthetic chemicals occurring in utero and early childhood have been linked to effects on life-long risk of obesity and metabolic abnormalities [9].

The matter of artificial reproductive techniques (ART) and their impact on childhood obesity has received increased attention [10]. An increase in body fat in children born by "in vitro" fertilization was reported by Ceelen et al., as compared to the controls [11]. Although there is little data, the findings are sufficiently compelling to add ART to the list of prenatal risk factors related to long-term outcomes.
