Uterine artery blood flow during pregnancy in high-altitude aymara women
Fecha
2003-02-19Autor
Wilson, Megan
Niermeyer, Susan
Armaza, J Fernando
López, Miriam
Vargas, Enrique
Moore, Lorna G
Metadatos
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Background.
Birth weight falls with increasing altitude as the result of
intrauterine growth restriction (IUGR) likely due, in turn, to lower uterine artery (UtA) blood flow. The altitude-associated birth weight decline
is least in the longest resident (in generations) groups, suggesting that
adaptations may have occurred that raise uteroplacental blood flow to
near sea-level values (Moore et al. HAMB 2001). Study Objective: Determine the factors responsible for raising UtA blood flow in Andean pregnant women, and whether the values near term resemble those of low-altitude residents. Methods: Measurements of the vessel diameters and
blood flow velocities (averaged throughout the cardiac cycle) were made
for the UtA, common iliac (CI), and external iliac (EI) arteries at 20, 30,
and 36 weeks of pregnancy and 3 months postpartumto measure the nonpregnant state, using Doppler ultrasound (ATL 3000 and an investigational Doppler Velocimeter). Results: UtA volumetric flow increased as a
result of an early enlargement of UtA diameter with a continued, progressive rise in flow velocity. There was a corresponding rise in CI flow,
which was increasingly directed to the UtA (see figure). The increase in
CI flow was due primarilyto an increase in vessel diameter. The near term
UtA volumetric flow
appears similar to that
of low-altitude residents (wk 36 value =
353 mL/min, Palmer
Ob Gyn 1992), consistent with our hypothesis. This suggests that
selection may have
acted on the factors responsible for raising
UtA diameter and flow
velocity. (HL60131,
TW01188)