Calcium-to-Creatinine Ratio in a Spot Sample of Urine, for Early Prediction of Hypertensive Disorders of Pregnancy: A Prospective Study

Abstract

Background

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.

Methods

This study was done on 112 patients presenting to the antenatal clinic in the Department of Obstetrics and Gynecology at Bangalore Baptist Hospital. A random urinary calcium-to-creatinine ratio of all the patients was analyzed. The urinary calcium level was analyzed by Arezano method, while creatinine was estimated by Jaffes method. A value of ≤0.04 was considered positive.

Results

116 patients were recruited in the study. Out of the 11 subjects with urinary CCR < 0.04, 7 developed gestational hypertension, 3 developed preeclampsia, and 1 remained normotensive. In 101 patients with CCR > 0.04, 1 developed gestational hypertension, none preeclampsia and 100 were normotensive. Four were lost to follow-up.

Interpretation and Conclusion

On statistical analysis, it was found that when CCR alone is taken as high-risk factor for prediction of preeclampsia, P < 0.001 was statistically significant, sensitivity was 80 %, specificity 98.04 %, PPV 80 %, NPV 98.04 %, and diagnostic accuracy 96.43 %. So this test was satisfactory as an early predictor for the development of preeclampsia.