Effect of a low protein diet during pregnancy of the rhesus monkey. II. Physiological adaptation of the infant.

Heart rate, respiratory rate, and ability to maintain body temperature were evaluated in six infants born to rhesus monkeys that had been fed a low protein diet throughout pregnancy. All infants were kept in incubations equipped with a "servo" control thermal unit that maintained the infants' skin temperature at 37.0 C (98.6 F). The thermal units were disconnected and the infants were exposed to room temperature (approximately 27 C) for 6-hr periods each day after 24 hr of age in order to determine the efficiency of thermal control mechanism. The thermal servo control units were "on" for a longer period of time in experimental animals than in control animals during the first 24 hr of life. Infants from mothers fed the low protein diets were also less able to maintain their own body temperatures after exposure to room temperature. This function was seriously compromised in two of the six experimental infants. The compromised temperature control mechanism seen in these infant monkeys is a serious and potentially lethal side-effect of protein-calorie malnutrition during pregnancy. The possible relationship of inadequate maternal nutrition to the inefficient thermal mechanism of certain "high risk" human newborns should be reevaluated.