GPx activities in both maternal and cord plasma have also been shown to be lower in preeclamptic pregnancies. Several retrospective studies from Turkey the United States and Australia of maternal plasma or placental tissue collected from normal pregnancy and preeclampsia report a reduction in GPx activity in preeclampsia. Our group recently conducted a retrospective cross sectional study in the United Kingdom of preeclamptic women and healthy controls as well as cord blood and placental tissue collected immediately after delivery. Total GPx activity in plasma and in placental tissue were significantly reduced in preeclampsia. Further prospective, longitudinal studies are required to elucidate a cause or effect relationship