Greater uterine artery blood flow during pregnancy in multigenerational (Andean) than shorter-term (European) high-altitude residents

Megan J. Wilson, Miriam Lopez, Marco Vargas, Colleen Julian, Wilma Tellez, Armando Rodriguez, Abigail Bigham, J. Fernando Armaza, Susan Niermeyer, Mark Shriver, Enrique Vargas, Lorna G. Moore

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

Multigenerational (Andean) compared with shorter-term (European) high-altitude residents exhibit less hypoxia-associated reductions in birth weight. Because differences in arterial O2 content are not responsible, we asked whether greater pregnancy-associated increases in uterine artery (UA) blood flow and O2 delivery were involved. Serial studies were conducted in 42 Andean and 26 European residents of La Paz, Bolivia (3600 m) at weeks 20, 30, 36 of pregnancy and 4 mo postpartum using Doppler ultrasound. There were no differences postpartum but Andean vs. European women had greater UA diameter (0.65 ± 0.01 vs. 0.56 ± 0.01 cm), cross-sectional area (33.1 ± 0.97 vs. 24.7 ± 1.18 mm2), and blood flow at week 36 (743 ± 87 vs. 474 ± 36 ml/min) (all P < 0.05) and thus 1.6-fold greater uteroplacental O2 delivery near term (126.82 ± 18.47 vs. 80.33 ± 8.69 ml O2·ml blood-1·min-1, P < 0.05). Andeans had greater common iliac (CI) flow and lower external iliac relative to CI flow (0.52 ± 0.11 vs. 0.95 ± 0.14, P < 0.05) than Europeans at week 36. After adjusting for gestational age, maternal height, and parity, Andean babies weighed 209 g more than the Europeans. Greater UA cross-sectional area at week 30 related positively to birth weight in Andeans (r = +0.39) but negatively in Europeans (r = -0.37) (both P < 0.01). We concluded that a greater pregnancy-associated increase in UA diameter raised UA blood flow and uteroplacental O2 delivery in the Andeans and contributed to their ability to maintain normal fetal growth under conditions of high-altitude hypoxia. These data implicate the involvement of genetic factors in protecting multigenerational populations from hypoxia-associated reductions in fetal growth, but future studies are required for confirmation and identification of the specific genes involved.

Original languageEnglish (US)
Pages (from-to)R1313-R1324
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume293
Issue number3
DOIs
StatePublished - Sep 2007

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

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