Low serum calcium and high parathyroid hormone levels in neonates fed 'humanized' cow's milk-based formula
B. L. Specker, R. C. Tsang, M. L. Ho, T. M. Landi and T. L. Gratton
Department of Pediatrics, University of Cincinnati Medical Center, OH 45267-0541.
We previously suggested that "late" neonatal hypocalcemia is related to a
low calcium-phosphorus ratio of current cow's milk-based formula compared
with human milk. However, there are no longitudinal studies of ionized
calcium and parathyroid hormone concentrations in neonates receiving
formulas with varying Ca/P ratios. Sixty-nine term neonates were studied
through 2 weeks of age, and formula-fed neonates were randomized at birth
to receive formula with molar ratios of 0.9, 1.2, or 1.4. Serum phosphate
concentrations on days 2 and 6 of age were higher, and ionized calcium
levels lower on days 6 and 14, in formula-fed vs human milk-fed neonates.
Serum intact parathyroid hormone level increased between days 2 and 6 in
formula-fed neonates compared with a decrease in human milk-fed neonates.
Serum parathyroid hormone level on day 6 correlated with phosphorus intake
among formula-fed neonates. No differences were noted in serum mineral or
hormone levels among formula-fed groups. We speculate that the lowering of
serum ionized calcium concentrations in neonates fed a modern "humanized"
cow's milk formula may be a factor in late neonatal hypocalcemia.
