Urinary calcium excretion decreases in preeclampsia. To determine the
predictability of preeclampsia with hypocalciuria, we investigated the
calcium to creatinine ratio and the calcium level of a spot urine sam
ple in 56 primigravid patients aged less than 25 years. Of these 56 ca
ses, 44 remained normotensive and preeclampsia developed in eight case
s. There were four cases of gestational hypertension and they are not
included in the statistical analysis. The mean age, the mean gestation
al age at entrance into the study, the mean urine calcium concentratio
n, the mean birthweight, and the mean gestational age at delivery were
similar between the normotensive and preeclamptic groups. The mean ca
lcium to creatinine ratio is found to be significantly lower in the pr
eeclamptic group (0.0475 +/- 0.0260) compared with the normotensive gr
oup (0.1466 +/- 0.1353; p <0.0001). A cutoff level of 0.066 for the ca
lcium to creatinine ratio with the use of a receiver operator curve yi
elded a sensitivity of 75%, a specificity of 86%, and a positive and n
egative predictive value of 55% and 95%, respectively. The results of
this study suggest that a single urine calcium to creatinine ratio mig
ht be an effective marker for predicting preeclampsia in a high-risk p
opulation.