Use of 24-hour urinary protein and calcium for prediction of preeclampsia.

OBJECTIVE To assess the efficacy of 24-hour urinary protein and calcium for the prediction of preeclampsia. MATERIALS AND METHODS Two hundred normotensive women at 20-28 weeks' gestation were enrolled in the study. All women were asked to collect a 24-hour urine sample. Urinary protein and calcium were measured and expressed as milligrams per 24 hours. Sensitivity, specificity and predictive values were calculated for each test, and cutoff values were calculated using receiver operating characteristic curves. RESULTS Twenty-one of the 200 women developed preeclampsia, including eight who developed severe preeclampsia and 13 who developed mild preeclampsia. Compared with the normotensive women (n = 179), the hypertensive patients (n = 21) had significantly lower urinary calcium excretion (167.23 +/- 80.63 mg vs. 277.43 +/- 60.38 mg) and higher proteinuria (351.14 +/- 41.58 mg vs. 296.33 +/- 30.03 mg). CONCLUSION A decrease in 24-hour urinary calcium and increase in protein between 20-28 weeks' gestation are risk factors for preeclampsia.