High Altitude During Pregnancy

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The challenge of high-altitude hypoxia

Again on passing the Great Headache Mountain, the little Headache Mountain, the Red Land and the Fever Slope, men’s bodies become feverish, they lose color and are attacked with headache and vomiting…1

Ch’ien Han Shu text (approximately 32–37 BC)

High-altitude hypoxia poses one of the greatest environmental threats to human survival. Barometric pressure decreases with ascending altitude, decreasing the Po2 and, in turn, oxygen availability in ambient air. This hypobaric hypoxia is the most

Influence of high altitude on pregnancy outcome

The clinical relevance of high-altitude hypoxia for pregnancy outcome is best illustrated by the 3-fold greater incidence of intrauterine growth restriction (IUGR) at high (≥2500 m) altitude relative to low altitude (Fig. 1).2, 3, 4, 5 IUGR, defined as birth weight less than the 10th percentile of sea-level values for a given gestational age and sex,6 is associated with a 4-fold increase in stillbirth and an 8- to 20-fold increase in neonatal mortality depending on the degree of growth

Unique physiologic compensations during high-altitude pregnancy

Successful pregnancy outcome at high altitude depends on maternal and, ultimately, fetal physiologic compensations for diminished oxygen availability and its secondary effects (eg, hypoxia-regulated gene expression). Failure to maintain maternal arterial oxygenation, impaired maternal vascular adaptation to pregnancy, and/or altered placental/fetal nutrient transport or consumption seem to be important factors for compromised fetal growth at high altitude.18, 19, 20, 21, 22

Highland ancestry protects fetal growth at high altitude

A unique dimension of high-altitude models to examine the effect of chronic hypoxia during human pregnancy is that the magnitude by which fetal growth declines with increasing elevation depends, in part, on the population ancestry.2, 21, 55, 56, 57 Such ancestry-related effects are informative not only for identifying physiologic traits that increase or decrease susceptibility to poor pregnancy outcome but also for determining the potential role of genetics in the modification of biologic

Summary

Chronic hypoxia of high-altitude residence significantly increases the risk of poor pregnancy outcome, despite profound physiologic compensations that fully or partially preserve maternal arterial oxygenation and blood flow to the developing fetus. High-altitude research models are invaluable to explore not only the detrimental aspects of chronic hypoxia during pregnancy but also the resolution of these effects. In particular, the protection against hypoxia-associated reductions in fetal growth

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References (61)

  • E. Krampl et al.

    Maternal plasma glucose at high altitude

    Br J Obstet Gynaecol

    (2001)
  • F. Ashcroft

    Life at the extremes: the science of survival

    (2002)
  • C.G. Julian et al.

    High-altitude ancestry protects against hypoxia-associated reductions in fetal growth

    Arch Dis Child Fetal Neonatal Ed

    (2007)
  • G.M. Jensen et al.

    The effect of high altitude and other risk factors on birthweight: independent or interactive effects?

    Am J Public Health

    (1997)
  • C. Unger et al.

    Altitude, low birth weight, and infant mortality in Colorado

    JAMA

    (1988)
  • E. Krampl

    Fetal biometry at 4300 m compared to sea level in Peru

    Ultrasound Obstet Gynecol

    (2000)
  • R.L. Williams et al.

    Fetal growth and perinatal viability in California

    Obstet Gynecol

    (1982)
  • W.M. Gilbert

    Pregnancy outcomes associated with intrauterine growth restriction

    Am J Obstet Gynecol

    (2003)
  • J.L. Lichty et al.

    Studies of babies born at high altitude

    AMA J Dis Child

    (1957)
  • D.A. Giussani et al.

    Effects of altitude versus economic status on birth weight and body shape at birth

    Pediatr Res

    (2001)
  • L.E. Keyes et al.

    Intrauterine growth restriction, preeclampsia and intrauterine mortality at high altitude in Bolivia

    Pediatr Res

    (2003)
  • K. Villar

    Eclampsia and pre-eclampsia: a health problem for 2000 years

  • P. Lopez-Jaramillo et al.

    Preventing pregnancy-induced hypertension: are there regional differences for this global problem?

    J Hypertens

    (2005)
  • S.H. Abman et al.

    Failure of postnatal adaptation of the pulmonary circulation after chronic intrauterine pulmonary hypertension in fetal lambs

    J Clin Invest

    (1989)
  • S. Niermeyer

    Cardiopulmonary transition in the high altitude infant

    High Alt Med Biol

    (2003)
  • S. Zamudio et al.

    Effect of altitude on uterine artery blood flow during normal pregnancy

    J Appl Physiol

    (1995)
  • M.J. Wilson et al.

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

    Am J Physiol Regul Integr Comp Physiol

    (2007)
  • C.G. Julian et al.

    Augmented uterine artery blood flow and oxygen delivery protect andeans from altitude-associated reductions in fetal growth

    Am J Physiol Regul Integr Comp Physiol

    (2009)
  • S. Zamudio et al.

    Hypoglycemia and the origin of hypoxia-induced reduction in human fetal growth

    PLoS One

    (2010)
  • S. Zamudio et al.

    Alterations in uteroplacental blood flow precede hypertension in preeclampsia at high altitude

    J Appl Physiol

    (1995)
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    This work was supported by grant number NIH HLBI-079647 and TW-01188.

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