THE EFFECT OF MILD STRESS DURING PREGNANCY ON BIRTH-WEIGHT AND NEUROMOTOR MATURATION IN RHESUS-MONKEY INFANTS (MACACA-MULATTA)

This prospective study investigated whether mild maternal stress during pregnancy could influence performance on of variety of developmental measures in rhesus monkey infants (Macaca mulatta). Twenty-four infants were tested during the first month of life for interactive, neuromotor, and temperamental characteristics and capabilities using instruments adopted directly from human neonatal assessments. Twelve infants were derived from mothers exposed during pregnancy to a mild stressor in the form of a daily 10-min removal from home cage and exposure to three unpredictable noise stimuli. Twelve infants were derived from mothers undisturbed during pregnancy. Prenatally stressed infants had lower birthweights, were delayed in self-feeding, were more distractible, and had lower scores on a Motor Maturity composite score when compared to offspring from undisturbed pregnancies. Close inspection of the Motor Maturity score revealed that low muscle tonus, poor coordination, and slow response speed characterized the prenatally stressed offspring.