Impact of Pregnancy at High Altitude on Placental Morphology in Non-native Women With and Without Preeclampsia

Tissot van Patot, M.C.; Valdez, M.; Becky, V.; Cindrova-Davies, T.; Johns, J.; Zwerdling, L.; Jauniaux, E.; Burton, G.J.

doi:10.1016/j.placenta.2009.04.002

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Volume 30, Issue 6 , Pages 523-528, June 2009

Impact of Pregnancy at High Altitude on Placental Morphology in Non-native Women With and Without Preeclampsia

M.C. Tissot van Patot
- Department of Anesthesiology, University of Colorado Denver Health Sciences Center, Aurora, CO, USA
- Corresponding author. Department of Anesthesiology, Campus Box 8602, Bldg. RC2, University of Colorado Denver, 12700 E. 19th Avenue, Room P15-7118, Aurora, CO 80045, USA. Tel.: +1 303 724 1762; fax: +1 303 724 2936.
M. Valdez
- Department of Anesthesiology, University of Colorado Denver Health Sciences Center, Aurora, CO, USA
V. Becky
- Department of Anesthesiology, University of Colorado Denver Health Sciences Center, Aurora, CO, USA
T. Cindrova-Davies
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
J. Johns
- Department of Obstetrics and Gynaecology, Institute for Women Health, University College London, London, UK
L. Zwerdling
- St. Vincent's General Hospital, Leadville, CO, USA
E. Jauniaux
- Department of Obstetrics and Gynaecology, Institute for Women Health, University College London, London, UK
G.J. Burton
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK

Accepted 2 April 2009. published online 13 May 2009.

Abstract

Previous data indicate that placentas from normotensive pregnancies in non-native women at 3100m (Leadville, CO) are not hypoxic at term, despite lower uterine artery blood flow, than in the same population at sea-level. We hypothesized that placental vascular development is greater at 3100m in compensation. Further, because the incidence of preeclampsia (PE), which has been linked to placental hypoxia, is 3–4 fold higher in this population, we investigated if preeclamptic placentas have altered vascularity compared to normotensive controls at 3100m. Placentas from normotensive (NT) pregnancies at sea-level, 1600 and 3100m, and late-onset preeclamptic placentas were collected at 3100m. Placental and birth weights were determined, and stereology performed on paraffin- and resin-embedded tissue. Both normal and preeclamptic placentas at high altitude were smaller than those at sea-level, and birth weights trended down with no change in the placental index. Volume fractions of the placental and villous compartments were similar between all conditions, but the absolute volume of each compartment was reduced at 3100m compared to sea-level. Villous volume was equivalent between sea-level and 1600m. There were no differences between PE and NT placentas at 3100m. Placental vascularity was similar at all altitudes, and the gas-exchange area was preserved at 1600m but not 3100m. Late-onset preeclampsia was not associated with placental changes at 3100m.