Effect of altitude on uterine artery blood flow during normal
pregnancy.
Zamudio, Stacy, Susan K. Palmer, Tarshi Droma, Elizabeth Stamm,
Carolyn Coffin, Lorna Grindlay Moore.
Department of Anesthesiology, University of Colorado Health
Sciences Center, Denver CO 80262 USA, Women's Health Research Center,
University of Colorado Health Sciences Center, Denver CO 80262 USA,
Department of Anthropology, University of Colorado at Denver, Denver,
CO 80217-3364 USA, Tibet Institute of Medical Sciences, Lhasa, Tibet,
P R China 850000, Department of Radiology and Ultrasound, University
of Colorado Health Sciences Center, Denver CO 80262 USA,
Cardiovascular Pulmonary Research Laboratory, University of Colorado
Health Sciences Center, Denver CO 80262 USA
APStracts 2:0112A, 1995.
To determine whether uterine blood flow was reduced and indices of
pelvic blood flow distribution altered in normotensive pregnancy at
high (3100 m) compared with low altitude (1600 m), we measured
uterine, common iliac and external iliac artery blood flow velocity
and diameters in women while pregnant and again postpartum. Pregnancy
increased uterine artery diameter, blood flow velocity, and
volumetric flow at both altitudes. Uterine artery blood flow velocity
was greater (69.0+2.2 vs. 59.4+3.0 cm/sec, P<.005), but diameter
was smaller at 3100 m than 1600 m (2.5+0.3 mm vs. 3.4+0.2 mm,
P<.005), resulting in volumetric flow that was one-third lower at
wk 36 of pregnancy (203 + 48 vs 312 + 22 ml/min, respectively, P <
0.01). Pregnancy increased common iliac blood flow velocity and
decreased external iliac artery blood flow velocity at both
altitudes. The uterine artery received a smaller percent of common
iliac flow at 3100 than 1600 m (46+7 vs. 74+6%, P < 0.005).
Gestational age was similar but birth weight was lower at 3100 m than
1600 m. Among subjects at 1600 m, variation in uterine blood flow
velocity correlated positively with infant birth weight. We concluded
that reduced uterine blood flow and altered pelvic blood flow
distribution during pregnancy at high altitude likely contributed to
the altitude-associated reduction in infant birth weight.
Received 22 June 1994; accepted in final form 6 March 1995.
APS Manuscript Number A618-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 21 March 1995.