Randomized trial of magnesium administration to prevent hypocalcemia in infants of diabetic mothers.

OBJECTIVE: Hypocalcemia is common in infants of diabetic mothers (IDMs) and may be caused by secondary hypoparathyroidism related to hypomagnesemia. This study was designed to test the hypothesis that prophylactic magnesium sulfate (MgSO4) administration at birth in IDMs with low cord magnesium concentrations will prevent neonatal hypocalcemia. STUDY DESIGN: In this randomized trial conducted in IDMs with a cord magnesium concentration of <0.74 mM (1.8 mg/dl), 26 subjects received 6 mg/kg elemental magnesium and 23 subjects received no treatment. Serum concentrations of total and ionized calcium, phosphorus, and magnesium were recorded at birth, by measuring the concentrations within the umbilical cord, and at 24 and 72 hours of age. RESULTS: The incidence of hypocalcemia at 72 hours was 0% (0 of 23) in the magnesium-treated group and 12.5% (2 of 16) in the group with no treatment (p = 0.16). There was no difference in mean serum calcium concentration at 72 hours between infants in the treated group and the group with no treatment (2.28 +/- 0.04 vs 2.22 +/- 0.05 mM; p = 0.39). The drop in serum calcium concentration from birth to 72 hours of age was less for the treated group (0.30 +/- 0.05 mM [1.23 +/- 0.18 mg/dl]) than the group with no treatment (0.45 +/- 0.05 mM [1.81 +/- 0.21 mg/dl]; p = 0.04). CONCLUSION: Administration of intramuscular MgSO4 to IDMs with cord magnesium <0.74 mM (1.8 mg/dl) does not reduce the incidence of hypocalcemia in infants of well-controlled diabetic mothers.

Trial on timing of introduction to solids and food type on infant growth.

OBJECTIVE: The optimal time and choice of solid foods to introduce to an infant's diet is unknown. The aim of this randomized trial was to determine whether early versus late introduction of solid foods and commercially prepared versus parent's choice of solid foods affects growth or body composition in the first year. METHODS: White infants (n = 165) were recruited before 3 months of age and were randomized to receive: 1) commercially prepared solid foods (commercial) from 3 to 12 months, 2) commercially prepared solid foods from 6 to 12 months, 3) parent's choice of solid foods (choice) from 3 to 12 months, or 4) parent's choice of solid foods from 6 to 12 months. Anthropometrics and body composition, using dual energy x-ray absorptiometry, were determined at 3, 6, and 12 months. Three-day diet diaries were completed at 3, 6, 9, and 12 months. RESULTS: There were no differences in growth or body composition between infants in early versus late introduction groups or commercial versus choice groups at any age. The total energy intake was not different among infants in the early compared with the late group at any age. Infants in the commercial group consumed less protein calories at 9 months (80 +/- 3 kcal/d vs 88 +/- 3 kcal/d) and 12 months 101 +/- 5 kcal/d vs 148 +/- 5 kcal/d), less fat calories at 12 months (263 +/- 10 kcal/d vs 343 +/- 10 kcal/d), and less total calories at 12 months (884 +/- 24 kcal/d vs 1022 +/- 25 kcal/d) compared with the choice group. CONCLUSION: The early introduction of solid foods to an infant's diet does not alter growth or body composition during the first year of life and results in a displacement of energy intake from formula. Infants consuming commercially prepared foods have a decreased caloric intake from protein and fat; however, despite this difference, there is no effect on growth or body composition.

Lessons from the late diagnosis of isovaleric acidemia in a five-year-old boy.

Chronic, intermittent isovaleric acidemia was undiagnosed in a boy with an increased anion gap metabolic acidosis until the boy was 5 years of age. This case emphasizes the importance of maintaining a high index of suspicion for inborn errors of metabolism in patients with metabolic acidosis, even in late childhood.