HIGH-ALTITUDE AND HYPERTENSION DURING PREGNANCY

Hypertensive complications of pregnancy are more common at high than l ow altitudes. Hypertension in pregnancy is associated with increased m aternal and fetal morbidity and mortality; thus natural selection may be operating against women who develop the disorder and their infants. It has long been hypothesized that chronic hypoxia due to residence a t high altitude predisposes women to develop hypertension during pregn ancy. Prior studies indicate that maternal adaptation to pregnancy is altered by residence at high altitude such that some physiological cha racteristics of women pregnant at high altitude resemble those of wome n who develop hypertension during pregnancy at low altitude. This pape r reviews data from studies, conducted over the past decade, which sup port a relationship between chronic hypoxia and hypertension during pr egnancy. The results suggest that both the requirements for successful adaptation to high altitude, as well as the effect of lowered P(O)2 d uring pregnancy, may contribute to the development of hypertension dur ing pregnancy. (C) 1995 Wiley-Liss, Inc.