Long-term metabolic consequences of being born small for gestational age.

This review highlights the evidence of linking small for gestational age (SGA) with metabolic/cardiovascular disturbances (dysmetabolic syndrome) in later life. The metabolic and cardiovascular complications associated with in utero undernutrition have been identified during the past 10 yr. Reduced fetal growth is independently associated with an increased risk of the development of cardiovascular diseases, the insulin-resistance syndrome, or one of its components: hypertension, dyslipidemia, impaired glucose tolerance, or type 2 diabetes. All of them appear to result from the initial development of insulin-resistance which appears as a key component underlying the metabolic complications. Although the mechanism remains unclear, there is some evidence that argues in favor of an active contribution of the adipose tissue in the emergence of insulin-resistance associated with in utero undernutrition, but this hypothesis remains to be further documented. From a broader point of view, several hypotheses have been proposed over the past 10 yr to understand this unexpected association. Each of them points to either a detrimental fetal environment or genetic susceptibilities or interactions between these two components as playing a critical role in this context. Although not confirmed, the hypothesis suggesting that this association could be the consequence of genetic/environmental interactions remains at the moment the most attractive.