EVALUATION OF MATERNAL SERUM CALCIUM, MAGNESIUM, AND THE CA:MG RATIO AS EARLY PREDICTORS OF PREECLAMPSIA SEVERITY

Abstract

Background: Preeclampsia is a pregnancy-specific hypertensive disorder with severe outcome closely related to systemic endothelial dysfunction and trace element imbalances. The study was aimed to evaluate maternal serum calcium, magnesium and calcium-to-magnesium (Ca:Mg) ratio as early biochemical predictors of severity of preeclampsia.
Methods: This was a prospective observational case control study conducted over a period of 6 months (July 2014 to December 2014) in Tertiary care center in Central India. The study included 100 pregnant women (>20 weeks gestation) divided into normotensive control group (n=50) and preeclampsia case group (n=50). To assess severity of the disease, the preeclampsia group was further divided into mild and severe groups (n = 30 and n = 20, respectively). Total calcium and magnesium concentrations were measured in maternal serum using photometric assays and the mathematical ratio of Ca:Mg was calculated.
Results: Mean serum calcium and serum magnesium were significantly lower in women with preeclampsia (8.16 ± 0.74 vs. 9.42 ± 0.58 mg/dL, p<0.001 and 1.62 ± 0.40 vs. 2.10 ± 0.32 mg/dL, p<0.001 respectively) than the normotensive controls. However, Ca:Mg ratio was significantly increased in preeclampsia group (5.23±0.88 vs. 4.54±0.65, p<0.001). There was a progressive statistically significant increase in the Ca:Mg ratio with the severity of disease and was significantly higher in severe preeclampsia than in mild preeclampsia (5.72±0.94 vs. 4.90±0.72, p=0.002).
Conclusion: Relative hypocalcemia and hypomagnesemia are the main features of preeclampsia in Central Indian population. The Ca:Mg ratio is a very sensitive dynamic biochemical marker which accurately reflects the progressive vasospasm and escalation of the disease and provides a robust cost effective screening tool for early risk stratification.