The Placenta in a Diabetic Pregnancy

Owing to its position between mother and fetus, the placenta is exposed to maternal and fetal derangements associated with diabetes. These lead to various structural and functional changes, including heavier weight, surface enlargement, and hypervascularization. The diabetic environment will affect the placenta depending on gestational age. Hence, unless the onset of diabetes preceded pregnancy and had been undetected, gestational diabetes may alter placental maturation later in gestation, whereas pre-gestational diabetes may additionally alter key processes early in gestation leading to a higher incidence of spontaneous abortions. Circulating maternal and fetal levels of insulin, IGF1, IGF2, and leptin are altered in diabetes and affect placental development. In this chapter, diabetes-induced changes in the insulin–IGF axis and leptin, and the consequences on placental function, will be discussed.