Pregnancy at high altitude in the Andes leads to increased total vessel density in healthy newborns

Abstract

The developing human fetus is able to cope with the physiological reduction in oxygen supply occurring in utero. However, it is not known if microvascularisation of the fetus is augmented when pregnancy occurs at high altitude. Fifty-three healthy term newborns in Puno, Peru (3,840m) were compared to sea level controls. Pre- and post-ductal arterial oxygen saturation (SpO2) was determined. Cerebral and calf muscle regional tissue oxygenation were measured using near infrared spectroscopy (NIRS). Skin microcirculation was non-invasively measured using Incident Dark Field imaging. Pre- and post-ductal SpO2 in Peruvian babies was 88.1% and 88.4% respectively, which was 10.4% and 9.7% lower than in newborns at sea level (p<0.001). Cerebral and regional oxygen saturation were significantly lower in the Peruvian newborns (cerebral 71.0 % vs. 74.9%; regional 68.5% vs. 76.0%, p<0.001). Transcutaneously measured total vessel density in the Peruvian newborns was 14% higher than that in the newborns born at sea level (29.7 vs. 26.0 mm/mm2; p≤ 0.001). This study demonstrates that microvascular vessel density in neonates born to mothers living at high altitude is higher than that in neonates born at sea level.