Birth in the Peruvian Andes: physical and behavioral consequences in the neonate.

Full-term neonates of both sexes born without complications to healthy mothers at about 4,300 m or 14,000 feet (O2 pressure = 82 mm Hg) and at 150 m or 490 feet (O2 pressure = 150 mm Hg) above sea level were evaluated at 24--36 and 48--60 hours of life. Anthropometric measurements were obtained, and behavioral responsivity was evaluated with the Brazelton Neonatal Behavioral Assessment Scale. The high-altitude infants were significantly lighter, shorter, and had a smaller arm circumference than the low-altitude infants. No differences were found in measurements of either head circumference or skin-fold thickness. In comparison with the low-altitude infants, the high-altitude infants presented more signs of behavioral immaturity in interactive and motoric processes. These results are similar to those reported for clinical cases of full-term underweight infants, newborns of toxemic mothers, and undernourished neonates.