THE EFFECT OF FEEDING ON OXYGEN CONSUMPTION, RQ AND PLASMA LEVELS OF GLUCOSE, FFA, AND D‐β‐HYDROXYBUTYRATE IN NEWBORN INFANTS OF DIABETIC MOTHERS AND SMALL FOR GESTATIONAL AGE INFANTS

Abstract

Eight infants of strictly controlled diabetic mothers (IDM), 8 infants of gestational diabetic mothers (IGDM) and 6 small for gestational age infants (SGA) were studied before the first feeding and during an early feeding regimen. In IDMs and IGDMs continuous monitoring from 2 hours up to 7 1/2 hours after birth before feeding revealed no consistent changes of Vo₂ and RQ. The groups of infants were studied on 4 different occasions: (I) 2 to 16 hours, (II) 1 to 2 days, (III) 3 to 4 days, and (IV) 7 to 11 days. Prefeeding Vo₂-values were not significantly different between each of the groups, but mean RQ was higher in IGDMs than in IDMs. Age of the infant and prefeeding RQ were inversely correlated (r=-0.537, p2 increased significantly in all groups. RQ decreased during the first 24 to 48 hours in all groups and rose thereafter with highest values at 7 to 11 days. Plasma levels of glucose, FFA, and D-β-hydroxybutyrate were not significantly different between each of the groups. The highest values for D-β-hydroxybutyrate were found at 1–2 days when the lowest RQ values were also recorded. D-β-hydroxybutyrate concentrations and RQ values (r= -0.648, p2 that reached a maximum at 1 to 1 1/2 hours after the feed, then slowly returned to pretest values. The rise in Vo₂ was accompanied by an increase in rectal temperature (0.4 to 1.5°C). Vo₂, RQ, and plasma levels of glucose, FFA, and D-β-hydroxybutyrate, were almost identical for each of the groups. We suggest: 1) That differences in feeding practice is the most likely explanation for the discrepancy between reported values for Vo₂, RQ, and circulating substrates in normal and low birth weight newborns. 2) That the rise in Vo₂ during the neonatal period, caused by feeding, reflects the cost of growth.