PIP: In developed countries, preeclampsia is the leading cause of maternal mortality and a major factor in perinatal mortality. The ability to predict clinical preeclampsia would enable increased surveillance of high-risk pregnant women and treatment in the early stages before preeclampsia leads to irreversible pathophysiological changes. In one study, a ratio of the urinary excretion of kallikrein to that of creatinine at 16-20 weeks' gestation of 170 or less identified 83% of women with preeclampsia with a positive predictive value of 91%. The same ratio predicted gestational hypertension without proteinuria with a sensitivity of 70% and a positive predictive value of 40%. The problem is that preeclampsia represents diverse pathogenetic processes, only some of which may be relevant to a particular predictive measure. Also problematic are the variable recurrence rates and clinical presentations in diverse population groups.