Increased oxygen free radical production during pregnancy may impair vascular reactivity in preeclamptic women

To determine whether enhanced oxidative stress during pregnancy impairs vascular endothelial function and improves after delivery in preeclamptic women, we measured serum parameters of oxidative stress and endothelial function during pregnancy and 1 month after delivery in women with or without preeclampsia. We evaluated 18 participants with uncomplicated pregnancies, 11 with mild preeclampsia and 13 with severe preeclampsia. The plasma concentrations of reactive oxygen metabolite derivatives (d-ROMs) were measured, and the biological antioxidant potential (BAP) was determined to evaluate the oxygen free radicals and antioxidants, respectively. Flow-mediated vasodilation (FMD) was also assessed as a marker of endothelial function. FMD was decreased significantly in both preeclamptic groups compared with control during pregnancy. FMD did not change after delivery in the control group, but it significantly increased after delivery in both the mildly and severely preeclamptic groups, nearing control levels 1 month after delivery (mild, 6.5±3.6-9.0±3.5%; severe, 4.3±3.3-9.7±2.6%). No changes in d-ROM concentrations were observed in the control group; however, the concentrations in both the mildly and severely preeclamptic groups significantly decreased to normal levels 1 month after delivery (mild, 562.0±106.5-430.5±90.5 CARR U (Carratelli units); severe, 681.0±239.0-411.8±69.7 CARR U). The plasma BAP levels did not change significantly in all three groups. A negative correlation between FMD and d-ROM concentrations was observed in the preeclamptic group, but not in the control group (r=-0.497; P<0.05). Our findings indicated that enhanced oxidative stress during pregnancy may impair endothelial function and improve after delivery in preeclamptic women.