A longitudinal study of antioxidant status during uncomplicated and hypertensive pregnancies

Background . To study the possible involvement of an (im)balance between oxidants and antioxidants in pre-eclampsia concentrations of intra- and extracellular blood antioxidants in women with uncomplicated and hypertensive pregnancies, they were studied preconceptionally and throughout pregnancy. Methods . In uncomplicated pregnancies ( n =19) and hypertensive pregnancies ( n =6) concentrations of whole blood and plasma thiols, plasma vitamins E and C, hemoglobin, and hematocrit were assessed at preconception, 6, 10, 20, and 37 weeks of gestational age, as well as six weeks postpartum. A repeated mixed model was used for statistical analysis. Results . Vitamin C and most whole blood and plasma thiol concentrations decreased during pregnancy, while vitamin E, whole blood oxidized cysteinyl-glycine and the ratio of free to oxidized homocysteine revealed a linear increase during pregnancy. Postpartum plasma cysteine and vitamin C levels and the ratio of free to oxidized levels of cysteine, cysteinyl-glycine, and glutathione were significantly (p <0.05) higher six weeks after delivery. Plasma cysteine and homocysteine, and whole blood oxidized cysteine and homocysteine levels were significantly (p <0.05) higher at 37 weeks of gestational age in the hypertensive group compared to those in the uncomplicated group. There were no other differences between the hypertensive and uncomplicated groups. Conclusion . In normal pregnancy there seems a balance between antioxidant and oxidant concentrations despite modest oxidative stress. In mildly hypertensive pregnancies a marginal imbalance may occur.

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