Babies born to native high-altitude mothers have decreased risk of low bi...( BETHESDA Md. (May 18 2009) Pregnant ...)

BETHESDA, Md. (May 18, 2009) Pregnant women who are indigenous to the Andes Mountains deliver more blood and oxygen to their fetuses at high altitude than do women of European descent. The study helps explain why babies of Andean descent born at high altitude weigh more than European babies born at altitude.

The research, published in The American Journal of Physiology-Regulatory, Integrative and Comparative Physiology found that at high altitude:

• the uterine artery of Andean women delivered more blood and oxygen to the fetus compared to women of European descent
• 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 fetus 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 question of why babies born at high altitude are smaller is not an academic one. Low birthweight is associated with higher rates of illness and mortality. By understanding this physiology, researchers hope to find out how to protect from reductions in fetal growth even in low-oxygen environments.

The study, "Augmented uterine artery blood flow and oxygen delivery protect Andeans from altitude-associated reductions in fetal growth." 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 Andrs, La Paz, Bolivia; Abigail Bigham and Mark Shriver of Pennsylvania State University; and Miriam Lopez of Clnica del Sur, La Paz, Bolivia. Dr. Yamashiro is also affiliated with Clinica Siran, Santa Cruz de la Sierra, Bolivia and Dr. Moore is also affiliated with Wake Forest University, Winston-Salem, North Carolina.

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