The purpose of this study is to measure maternal oxygen transport which directly influences intrauterine growth at high altitude. The study will test the hypothesis that fetal growth retardation at high altitude stems from a decrease in fetal oxygen supply caused by a reduction in uterine blood flow. Pregnant women living at 10,200 feet will participate in the study. Measurement of maternal blood flow will be conducted through a noninvasive technique using an ultrasound instrument which measures mean blood flow velocity. The instrument can be positioned to measure flow in the uterine artery which supplies blood to the fetus. %%% Studies at high altitude are of particular interest to anthropologists because they help us to understand mechanisms (both cultural and physiological) by which populations adapt to a specific environmental stress, hypoxia. Fetal growth retardation is one of the most well-documented effects of high altitude. The mechanism by which this retardation takes place is not currently known. This study will address factors affecting blood flow to the fetus and their relationship to infant birth weight at high altitude.
