In order to investigate the role of placental isoferritin (PLF) in pathogenesis of pre-eclampsia and/or intrauterine growth retardation (IUGR) and its earlier predictive value, a prospective double-blinded study was performed. In 120 initial normal pregnant women at earlier third trimester (from 24 to 34 weeks), plasma placental isoferritin and nitric oxide (NO) metabolites (nitrite/nitrate) (NO 2 -/NO 3 -) were examined by using ELISA and Criess assay respectively. The outcome of pregnancies and birth weight of their infants were followed up. The receiver operating characteristic curves (ROC) and predictive values of PLF predicting the outcome of pregnancy with IUGR, pre-eclampsia were analyzed. Results showed that in 120 initial normal pregnant women, IUGR occurred in 15 pregnant women (IUGR group) and pre-eclampsia in 19 (pre-eclampsia group), and the remaining 86 had normal pregnancy (normal group). The levels of plasma placental isoferritin were significantly decreased in IUGR group (260.01±58.95) μg/ml and pre-eclampsia group (285.31±53.73) μg/ml as compared with those in normal group (775.62±89.32) μg/ml at earlier third trimester (both P<0.01). The levels of plasma NO were significantly increased in IUGR group (61.57±46.22) μmol/L and pre-eclampsia group (58.37±30.52) μmol/L as compared with those in the normal group (35.29±24.46) μmol/L (both P<0.01). There was no significant difference in plasma placental isoferritin and NO levels between IUGR group and pre-eclampsic group (both P>0 05). The plasma placental isoferritin was negatively correlated with NO levels (r=0.329,P<0 01). The areas under ROC of PLF predicting IUGR and pre-eclampsia were 0.977 and 0.905 respectively. At the cut point of 400 μg/ml PLF level, the sensitivity, specificity, positive predictive value, negative predictive value and Kappa index of PLF levels predicting the outcome of pregnancy with pre-eclampsia were 100 %, 85.15 %, 55.88 %, 100 % and 0.645 respectively. At the cut point of 390 μg/ml PLF level, the sensitivity, specificity, positive predictive value, negative predictive value and Kappa index of PLF levels predicting the outcome of pregnancy with IUGR were 100 %, 81.9 %, 44.12 %, 100 % and 0.663 respectively. It was concluded that the decrease of plasma placental isoferritin levels at earlier third trimester was associated with IUGR and/or pre-eclampsia, and the endothelial cell damage may be one of its mechanisms. The plasma PLF level can be used as an earlier predictor for screening of IUGR and/or pre-eclampsia. In order to investigate the role of placental isoferritin (PLF) in pathogenesis of pre-eclampsia and / or intrauterine growth retardation (IUGR) and its earlier predictive value, a prospective double-blinded study was performed. In 120 initial normal pregnant women at earlier Third trimester (from 24 to 34 weeks), plasma placental isoferritin and nitric oxide (NO) metabolites (nitrite / nitrate) (NO 2 - / NO 3 -) were examined by using ELISA and Criess assay respectively. The outcome of pregnancies and birth The result of that receiver operating characteristic curves (ROC) and predictive values ​​of PLF predicting the outcome of pregnancy with IUGR, pre-eclampsia were analyzed. Results showed that in 120 initial normal pregnant women, IUGR occurred in 15 pregnant women (IUGR group) and pre-eclampsia in 19 (pre-eclampsia group), and the remaining 86 had normal pregnancy (normal group). The levels of plasma placental isoferritin were significantly decreased in The IUGR group (260.01 ± 58.95) μg / ml and pre-eclampsia group (285.31 ± 53.73) μg / ml as compared to those in normal group (775.62 ± 89.32) μg / ml at earlier third trimester (both P <0.01) Levels of plasma NO were significantly increased in IUGR group (61.57 ± 46.22) μmol / L and pre-eclampsia group (58.37 ± 30.52) μmol / L as compared to those in the normal group (35.29 ± 24.46) μmol / L <0.01). There was no significant difference in plasma placental isoferritin and NO levels between IUGR group and pre-eclampsic group (both P> 0.05). The plasma placental isoferritin was negatively correlated with NO levels (r = 0.329, P <0 01). The areas under ROC of PLF predicting IUGR and pre-eclampsia were 0.977 and 0.905 respectively. At the cut point of 400 μg / ml PLF level, the sensitivity, specificity, positive predictive value, negative predictive value and Kappa index of PLF levels predicting the outcome of pregnancy with pre-eclampsia were 100%, 85.15%, 55.88%, 100% and 0.645 pens y. At the cutPLF level, the sensitivity, specificity, positive predictive value, negative predictive value and Kappa index of PLF levels predicting the outcome of pregnancy with IUGR were 100%, 81.9%, 44.12%, 100% and 0.663 respectively. It was concluded that the decrease of plasma placental isoferritin levels at earlier third trimester was associated with IUGR and / or pre-eclampsia, and the endothelial cell damage may be one of its mechanisms. The plasma PLF level can be used as an earlier predictor for screening of IUGR and / or pre-eclampsia.