MPO and preeclampsia: Previous studies measuring MPO in preeclampsia have reported conflicting results; some studies have reported no difference in MPO in preeclampsia in samples taken at 24 weeks or later in the third trimester28,29, whereas Gandley et al., reported a 3-fold increase in circulating MPO levels in women with preeclampsia compared to matched healthy controls at 32–38 weeks’ gestation30.