PTH and fetal growth restriction: • Prematurity • Intrauterine growth restriction • Sepsis • Perinatal asphyxia causing cellular damage and release of intracellular phosphate • Iatrogenic:   ∘ Transfusions with citrate blood products    ∘ Lipid infusions    ∘ Loop diuretics • Maternal factors:   ∘ Severe Vitamin D deficiency    ∘ Pre-eclampsia    ∘ Gestational diabetes associated with hypomagnesaemia    ∘ Hyperparathyroidism suppressing infant PTH synthesis    ∘ Anti-convulsants    ∘ High dose antacids