Perinatal calcium (Ca), phosphorus (P), and magnesium (Mg) metabolism involves an intricate and complex biological system of interrelated hormones and growth factors that regulate the concentrations of these minerals in the tissues of the mother, fetus, and neonate. Mineral metabolism depends on the availability of mineral substrates and interactions with hormones and growth factors including parathyroid hormone (PTH), calcitonin (CT), 1,25 dihydroxyvitamin D (1,25(OH)2D), insulin-like growth factors (IGFs) and possibly leptins. Understanding of the perinatal physiology of these minerals is important in the prevention and management of mineral disorders in the neonate.
In this chapter we review the perinatal physiology of Ca, P, and Mg metabolism in the fetus and neonate and offer a practical approach to the pathophysiology and management of Ca, P, and Mg disorders. We also review the current nutritional requirements of these minerals for enteral as well as parenteral nutrition. Finally, we review normal bone physiology, and discuss the pathophysiology, prevention, and management of metabolic bone disease or rickets/ osteopenia of prematurity.
Mineral, vitamin D and bone physiology
Body mineral content
Calcium is the fifth most abundant inorganic element in the human body. The adult human body contains about 1200 g of calcium (19 g of Ca per kg body weight). The total body Ca content in a full-term newborn is approximately 28 g, almost all of which (99%) resides in bone (8 g of Ca per kg body weight) where it serves structural and metabolic functions.