Estriol levels of cord blood, maternal venous blood, and amniotic fluid at delivery at high altitude

Effects of Altitude versus Economic Status on Birth Weight and Body Shape at Birth

“…Thus, it can be inferred from past and present observations that fetal growth retardation at high altitude may occur primarily in late gestation and may reflect maternoplacental insufficiency to meet the fetal oxygen demands at this time. Potential mechanisms may include a reduction in the transplacental oxygen partial pressure gradient (56) and/or depressed uteroplacental vasodilators (57,58) leading to reduced uterine blood flow (32,59), all of which have been reported in high-altitude pregnancy. It is possible that this unmatched fetal oxygen demand may trigger the release of fetoplacental hormones and factors that control tissue accretion and differentiation in the fetus during late gestation, such as insulin, thyroxine, cortisol, and IGF (60,61).…”