The Relationship of Birth Weight, Body Shape and Body Composition at Birth to Altitude in Saudi Arabia

The objective of this work was to study the effect of high altitude on full term birth weight, body shape and body composition of newborn infants. Twenty five healthy pregnant Saudi women and their healthy newborns from high altitude (2850-3150 m) and equal numbers from low altitude (500 m). For each pregnant woman haemoglobin concentration, haematocrit value and blood pressures were measured and recorded immediately after admission to hospital for delivery. Fetal haemoglobin concentration and haematocrit value were determined immediately after delivery. Determination of the newborn’s body shape and composition were made from anthropometric measurements which were performed two hours after delivery. Placental weight was determined immediately after its delivery. Placentae were then examined histologically. Compared with their respectives from lowland, the pregnant women from high altitude and their placentae showed haemotogical and histological changes suggestive of maternal and placental hypoxia respectively. There was no haematological evidence suggesting that the high altitude fetuses experienced a greater degree of hypoxia in utero than did the low altitude fetuses. Compared with lowland newborns highland newborns were significantly lighter but fatter and have significantly greater head circumference: birth weight ratios and abdominal circumferences. These differences in body physique between high and lowland neoborns appeared to be mainly secondary to placental hypoxia resulting from maternal hypoxia which in turn was caused by high altitude hypoxia. The altered body physique at birth due to high altitude hypoxia appeared to be not mediated by fetal hypoxia, but possibly by other mechanisms induced by placental hypoxia.