Intrauterine diabetic environment confers risks for type 2 diabetes mellitus and obesity in the offspring, in addition to genetic susceptibility

Numerous studies have reported that offspring whose mothers had type 2 diab etes mellitus (DM) are more likely to develop type 2 DM, impaired glucose t olerance, and obesity at an early age than offspring whose fathers had DM. Exposure to the diabetic intrauterine environment has been shown to be an i mportant risk factor for all these conditions. To what extent transmission of type 2 DM from mother to offspring is the effect of genetic inheritance and to what extent it is the long-term consequence of exposure to maternal hyperglycemia is still uncertain. There are, of course, interactions betwee n the diabetic intrauterine environment and genetics. Several data in exper imental animals as well as in humans suggest, however, that exposure of the fetus to the mother's DM confers a risk for type 2 DM and obesity that is above any genetically transmitted susceptibility. In the Pima Indian popula tion much of the increase in childhood type 2 DM can be attributed to the d iabetic intrauterine environment. This suggests that intensive glucose cont rol during pregnancy might have extended beneficial effects, contributing t o a decrease in the prevalence of childhood type 2 DM.