Preeclampsia is a hypertensive disorder in pregnant women, which can be the leading cause of maternal and neonatal death or premature birth. Although the cause of preeclampsia is still not clear, local or systemic oxidative stress may explain the pathological features associated with this complication. However, it is not clear whether oxidative stress is the cause or the result of preeclampsia. For this purpose, the present meta-analysis was intended to evaluate the oxidant and antioxidant status in women with preeclampsia. Relevant studies were identified after a preliminary investigation of research articles published up to September 2017. In the overall analysis, including 2953 cases and 3621 controls, a statistically significant reduction in total antioxidant capacity, nitric oxide, superoxide dismutase, glutathione, vitamin E and C was observed in preeclampsia women. On the other hand, a statistically significant increase in malondialdehyde, protein carbonyl, total peroxide, glutathione peroxidase, catalase and uric acid were observed in preeclampsia women. The increased products of oxidative stress, which were found in the present meta-analysis might be an underlying mechanism for endothelial dysfunction in preeclampsia. This meta-analysis provides a scientific support that primary reduction of antioxidant capacity and increased levels of oxidative stress products may induce a condition in which the pathways responsible for blood pressure homeostasis are disrupted. In conclusion, it is hypothesized when oxidative stress is established, a protective response is induced by increasing some antioxidants. Further studies are warranted to investigate the role of dietary supplementation and genetic variation in women with different ethnicity.
