Hypertensive disorders complicate 5-10 % of all pregnancies. Various methods for screening have been studied to identify pregnant women at risk of development of preeclampsia, but no ideal screening test has been identified so far. The objective of this study was to determine the efficacy of urinary calcium-to-creatinine ratio, in a spot urine sample, for the prediction of preeclampsia in asymptomatic pregnant women between 18 and 24 weeks of gestation.