Neonatal hypomagnesaemia

**Definition:** Defined as serum magnesium levels less than 0.66 mmol/L (1.6 mg/L) in neonates. Symptoms usually do not develop until serum Magnesium (Mg) levels fall below 0.49 mmol/L (1.2 mg/L). This is usually transient but can cause symptoms similar to those of hypocalcaemia.