In the study, researchers found that at high altitude the uterine artery of women indigenous to the Andes Mountains delivered more blood and oxygen to the foetus compared to women of European descent.
This helps explain why babies of Andean descent born at high altitude weigh more than European babies born at altitude, say researchers.
The babies of Andean women weighed an average of nine ounces more at birth the greater the mother's Andean heritage, the greater the uterine artery blood flow, the greater the oxygen delivery to the foetus and the greater the baby's birth weight.
These differences between the Andean and European women and their babies did not exist at low altitude.
The study was done by Colleen Glyde Julian, Megan J. Wilson, Henry Yamashiro and Lorna G. Moore of the University of Colorado; Wilma Tellez, Armando Rodriguez and Enrique Vargas of Universidad Mayor de San Andris, La Paz, Bolivia; Abigail Bigham and Mark Shriver of Pennsylvania State University; and Miriam Lopez of Clmnica del Sur, La Paz, Bolivia. Dr. Yamashiro is also affiliated with Clinica Siranm, Santa Cruz de la Sierra, Bolivia and Dr. Moore is also affiliated with Wake Forest University, Winston-Salem, North Carolina.
The study has been published in The American Journal of Physiology-Regulatory.