Feeding, growth, and biochemical studies in very low birthweight infants.

Fifty infants of gestational age 28 to 32 weeks and birthweight less than 1501 g were reviewed on the expected date of delivery and at conceptional ages of 4, 8, and 12 months. All infants were at home by the expected delivery date, were fed on demand, and weighed regularly. On the expected delivery date and at 4 months, the amounts of formula milk and weaning food accepted were recorded; energy and protein intakes were calculated; and serum sodium, potassium, urea, protein, and osmolality were measured. The birthweight of these infants ranged between the 3rd and 75th centiles (on average about the 20th) but at the expected delivery date was, on average, below the 3rd centile. Infants who had been weaned in the first 4 months after the expected delivery date (n = 26) had similar energy and protein intakes and similar biochemical indices to those weaned later (n = 24). They achieved catch up growth (below 3rd to 10-25th centile) by 1 year, irrespective of the time of weaning and without any differences in metabolic 'stress'.