Introduction & Objectives: Preeclampsia (PE) is known as multi system disorder complicated with hypertension and proteinuria after 20 week that occur on 2-8% of pregnancies. It is major cause of premature birth, prenatal death maternal and fetal mortality and morbidity. Oxidative stress play a significant role in the etiology of preeclampsia. Some studies have investigated the association between microsomal epoxide hydrolase (EPHX1) Arg139His polymorphism and preeclampsia. We therefore performed meta-analysis of clinical studies to investigate the association between the polymorphism of EPHX1 and the risk of preeclampsia. Materials & Methods: To identify all studies that investigated the association of EPHX1 Arg139His polymorphism and preeclampsia, electronic databases including PubMed, Scopus, Elsevier, Springer and Google Scholar were searched by two independent authors to find relevant publications. Four studies evaluated the epoxide hydrolase gene polymorphism and preeclampsia. Data analysis was performed using Comprehensive Meta-Analysis package, version 2. Results: The results emerged that EPHX1 Arg139His polymorphism was significantly associated with the increased risk of preeclampsia in dominant model (OR = 1.290; p = 0.05). However, there was no significant inter-study heterogeneity for this genetic model (I-squared= 40.383%, PHet= 0.169). The Begg’s funnel plot was symmetric and the Egger’s test was indicative of no publication bias among data set. Conclusion: In summary, EPHX1 Arg139His polymorphism is positively associated with the increased risk of pre-eclampsia among pregnant women, especially the homozygous carriers. So, genetic polymorphisms, which influence the activities of microsomal epoxide hydrolase may lead to the preeclampsia.
