Placental programming of chronic diseases, cancer and lifespan: a review.

Particular paths of fetal growth are now known to predict a range of disorders in adult life. This is thought to reflect fetal programming, the phenomenon whereby nutrition and other influences during development set the body's organs and systems for life. The thesis of this review is that normal variations in the processes of placental development lead to variations in the supply of nutrients to the fetus and programme a small number of key systems that are linked to later disease. A baby's growth and nutrition depend both on the function of the placenta, reflected in its gross morphology at birth, and on the mother's lifetime nutrition, reflected in her height and weight. In many studies, the effects of placental size and shape on later disease have been examined within different categories of mother's body size. The review shows that variations in gross placental morphology at birth predict a wide range of disorders in later life. Any particular placental phenotype seems to predict a limited number of diseases. Further research into the links between the processes of placentation and the morphology of the placenta at birth is now required. We need to know more about the relative importance of nutrient flow, nutrient balance and the timing of nutritional events in determining disorders in later life. We also need to understand why, compared to other placental mammals, the human placenta is so variable in its morphology and functional capacity.