The infant's self-regulation of food intake and weight gain. Difference in metabolic balance after growth constraint or acceleration in utero.

Methods of infant feeding, volume of milk intake, the introduction of solid supplements, and weight gain since birth have been studied in 191 babies at the age of 2 months. There were four groups: a hospital sample infants born to women who had been hypertensive during pregnancy, and infants who had been small-for-dates (S.F.D.) or large-for-dates (L.F.D.) at birth. Among bottle-feeders, S.F.D. infants took significantly more milk per kilogramme body-weight than infants in the hospital sample and hypertensive series; L.F.D. infants took significantly less. Within each group there was a negative correlation between actual weight at 2 months and milk intake per kilogramme body-weight. These findings are at variance with previous studies made on normal babies. Mean weight gain per kilogramme birth-weight per day was significantly increased in the S.F.D. series and reduced in the L.F.D. series compared with the hospital sample. Although mean milk intake per day at the age of 2 months was less for S.F.D. babies than for L.F.D. babies, mean weight gain per day was greater for S.F.D babies. In both extreme groups there was a tendency for breast-fed babies to revert towards the median faster than bottle-fed babies. These feeding and growth patterns of S.F.D. and L.F.D. babies suggest that there are powerful self-regulatory controls within the infant, and that the metabolic balance of S.F.D. infants is different from that of L.F.D. infants in the early postnatal months.