As noted in Chapter 85, abnormalities of magnesium (Mg+2) and calcium (Ca+2) metabolism are commonly seen in the neonatal intensive care unit. Calcium disturbances may be mirrored by magnesium, as in hypocalcemia with hypomagnesemia or hypercalcemia with hypermagnesemia. Infants of diabetic mothers (IDMs) and infants with intrauterine growth restriction (IUGR) may present with hypocalcemia, hypomagnesemia, or both. Abnormalities in serum values for Ca+2 and Mg+2 are of concern in any infant and warrant further investigation.