Increases in urinary creatinine and blood pressure during early pregnancy in pre-eclampsia

Background: It is important to predict the development of pre-eclampsia (PE) during early pregnancy to prevent its occurrence later on. In this study, we studied urinary biochemical parameters and blood pressure (BP) during and after pregnancy to find useful parameters for predicting PE. Methods: A case-control study was performed in 25 PE patients and 172 normotensive pregnant women. Twelve biochemical parameters were measured in spot urine, and the systolic and diastolic BPs were measured using an automated device during pregnancy and six to eight weeks after birth. Results: A multiple logistic regression analysis showed that the combinations of urinary creatinine (Cr) and systolic BP (SBP) in the first trimester of pregnancy (8.9 +/- 2.6 weeks), and of urinary inorganic phosphorus (IP)/Cr and SBP in the second trimester of pregnancy (19.0 +/- 1.6 weeks) were useful for predicting PE. The area under the curve in the receiver operator characteristic curve of the combination of urinary Cr and SBP in the first trimester was 0.85 (95% confidence interval [CI] 0.74-0.96), and that of the combination of urinary IP/Cr and SBP in the second trimester was 0.91 (95% CI: 0.86-0.97). When used 249 mg/dL in urinary Cr and 128 mmHg in SBP as their cut-off points, the combination in the first trimester increased the accuracy (sensitivity 75% and specificity 95%) in predicting PE, as compared with that of urinary Cr (29%, 99%) or SBP (50%, 98%). Conclusions: Combination of urinary Cr and SBP in early pregnancy and that of urinary IP/Cr and SBP in mid-pregnancy are useful for the prediction of PE.