Chapter 8 Skeletal Physiology Fetus and Neonate American

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Chapter 8 Skeletal Physiology: Fetus and Neonate © American Society for Bone and Mineral

Chapter 8 Skeletal Physiology: Fetus and Neonate © American Society for Bone and Mineral Research Contributed by CS Kovacs

Fetal Mineral Metabolism n n n Serum Ca, Mg, P are normally higher than

Fetal Mineral Metabolism n n n Serum Ca, Mg, P are normally higher than adult (maternal) levels PTH and calcitriol are normally low PTHr. P circulates at higher levels than PTH Calcium is actively transferred across the placenta in part due to actions of PTHr. P The skeleton rapidly mineralizes during the 3 rd trimester © American Society for Bone and Mineral Research Contributed by CS Kovacs

Neonatal Mineral Metabolism n n n Ionized calcium falls at birth with onset of

Neonatal Mineral Metabolism n n n Ionized calcium falls at birth with onset of breathing PTH and calcitriol increase and ionized calcium rises to adult level over 24 -48 hr PTHr. P becomes undetectable at some time point postnatally Intestine gradually turns on active absorption of calcium Skeleton continues to accrete mineral at a rate similar to late-term fetus © American Society for Bone and Mineral Research Contributed by CS Kovacs

Fetal and Neonatal Disorders of Mineral Metabolism n n Fetus n Maternal hypercalcemia suppresses

Fetal and Neonatal Disorders of Mineral Metabolism n n Fetus n Maternal hypercalcemia suppresses fetal parathyroids n Maternal hypocalcemia can cause fetal hyperparathyroidism and demineralization Neonate n Fetal hypo- or hyperparathyroidism manifests n Vitamin D disorders may not manifest until postnatally n Preterm infants are prone to metabolic bone disease and hypocalcemia © American Society for Bone and Mineral Research Contributed by CS Kovacs