Plasma and placental nitric oxide levels in women with and without pre-eclampsia living at different altitudes.

Objective: To investigate the nitric oxide (NO) levels in the plasma and the placentas of pregnant women with pre-eclampsia and women without pre-eclampsia, and to determine the effect of high or low altitude of residence.
Methods: NO was determined by chemoluminescence and group comparisons were performed.
Results: Women with pre-eclampsia (n=63) had higher plasma NO levels (38.6+/-17.44 vs 30.6+/-12.44 micromol/L, P=0.004) and higher placental NO levels (38.5+/-17.0 vs 24.3+/-7.16 ng/mg protein, P<0.05) compared with women without pre-eclampsia. A similar trend was found when comparisons were made according to altitude of residence. NO levels were significantly higher in the plasma of pre-eclamptic women living at sea level (41.11+/-18.78 vs 28.96+/-9.57 micromol/L, P=0.003), and in the placentas of women living at high altitude (39.51+/-16.98 vs 21.91+/-6.64 ng/mg protein, P<0.0001).
Conclusion: Women with pre-eclampsia had higher plasma and placental NO levels and the differences were associated with altitude of residence.