Objective: To evaluate the effect of high altitude on uterine and umbilical artery blood flow dynamics during normal pregnancy.
Method: Uterine artery blood flow parameters of the pregnant (34) and nonpregnant (37) subjects and umbilical artery blood flow parameters of 119 subjects living at high altitude or at low altitude were measured with color Doppler flow imaging system.
Results: Uterine artery diameter, blood flow volume increased during pregnancy at both altitude, and uterine artery blood flow volume and diameter were smaller at high altitude than at low altitude [(0.35 +/- 0.04) cm vs (0.45 +/- 0.04) cm, (280 +/- 48) ml/min vs (425 +/- 55) ml/min, P < 0.01]. Umbilical artery blood flow velocity systolic to diastolic (S/D) value, resistant index of different pregnant period were greater at high altitude than at low altitude (P < 0.01).
Conclusion: High altitude has effect on placental and infant blood flow that causes the decrease of placental blood infusion and the increase of uterine and umbilical artery flow velocity S/D and reactive index.