Increased Heinz body formation and impaired erythrocyte pentose phosphate shunt function during pregnancy.

The erythrocytes of 90 pregnant women were evaluated for the presence of in vivo or in vitro oxidant damage. The reduced glutathione (P less than 0.005) and the membrane reduced sulfhydryl (P less than 0.001) concentrations were decreased in fresh erythrocytes. Following incubation with acetylphenylhydrazine, Heinz body formation was significantly increased (P less than 0.001). Both the increase in Heinz body formation and the reduction in membrane reduced sulfhydryl content correlated strongly with duration of pregnancy. Glucose consumption was significantly decreased before, but not after, new methylene blue stimulation. Pentose phosphate shunt activity was impaired both before (P less than 0.05) and after (P less than 0.001) stimulation. No changes were observed in pentose phosphate recycling. The only alteration observed in the activity of the enzymes of the pentose shunt was an elevation of 6-phosphogluconate dehydrogenase activity. Although the clinical significance of these findings remains to be determined, medications with an oxidant potential should be used judiciously during gestation.