In another study comparing pregnant women with IUGR and a control group, it was stated that the level of malondialdehyde (MDA), which is a marker of lipid peroxidation, and the activities of xanthine oxidase (XO), which is an oxidant enzyme, and glutathione peroxidase (GSH-Px), which is one of the antioxidant enzymes, were significantly increased both in maternal circulation and placental tissue [22]. This evidence concerns the gene XDH and fetal growth restriction.