Lower uterine artery blood flow and higher endothelin relative to nitric oxide metabolite levels are associated with reductions in birth weight at high altitude.
Am J Physiol Regul Integr Comp Physiol
; 295(3): R906-15, 2008 Sep.
Article
em En
| MEDLINE
| ID: mdl-18579652
ABSTRACT
Reduced uteroplacental blood flow is hypothesized to play a key role in altitude-associated fetal growth restriction. It is unknown whether reduced blood flow is a cause or consequence of reduced fetal size. We asked whether determinants of uteroplacental blood flow were altered prior to reduced fetal growth and whether vasoactive and/or angiogenic factors were involved. Women residing at low (LA; 1,600 m, n = 18) or high altitude (HA; 3,100 m, n = 25) were studied during pregnancy (20, 30, and 36 wk) and 4 mo postpartum (PP) using Doppler ultrasound. In each study, endothelin (ET-1), nitric oxide metabolites (NO(x)), soluble fms-like tyrosine kinase (sFlt-1) and placental growth factor (PlGF) levels were quantified. At HA, birth weights were lower (P < 0.01) and small-for-gestational age was more common (P < 0.05) compared with LA. HA was associated with lower uterine artery (UA) diameter (P < 0.01) and blood flow (P < 0.05). Altitude did not affect ET-1, sFlt-1 or PlGF; however, ET-1/NO(x) was greater and NO(x) lower during pregnancy and PP at HA vs. LA. ET-1/NO(x) was negatively associated with birth weight (20 wk, P < 0.01; 36 wk, P = 0.05) at LA and HA combined. At HA, UA blood flow (30 wk) was positively associated with birth weight (dagger). UA blood flow and ET-1/NO(x) levels accounted for 45% (20 wk) and 32% (30 wk) of birth weight variation at LA and HA combined, primarily attributed to effects at HA. We concluded that elevated ET-1/NO(x) and altered determinants of uteroplacental blood flow occur prior to altitude-associated reductions in fetal growth, and therefore, they are likely a cause rather than a consequence of smaller fetal size.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Útero
/
Peso ao Nascer
/
Endotelina-1
/
Altitude
/
Retardo do Crescimento Fetal
/
Óxido Nítrico
Tipo de estudo:
Diagnostic_studies
/
Risk_factors_studies
Limite:
Adult
/
Female
/
Humans
/
Newborn
/
Pregnancy
País/Região como assunto:
America do norte
Idioma:
En
Revista:
Am J Physiol Regul Integr Comp Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Estados Unidos