Comparison of Serum Calcium-Magnesium Ratio in Women with and without Preeclampsia

Serum Calcium-Magnesium Ratio in Preeclamptic Women

Abstract

Preeclampsia remains a major cause of maternal and perinatal morbidity, and altered calcium and magnesium balance may contribute to its pathophysiology. Objective: To compare serum calcium, serum magnesium, and the calcium-to-magnesium ratio between women with preeclampsia and normotensive pregnant women. Methods:  A comparative cross-sectional study was conducted in the Department of Obstetrics and Gynecology at a tertiary care hospital from July to December 2025. Using non-probability consecutive sampling, 52 women at or beyond 24 weeks’ gestation were enrolled. Cases were diagnosed with preeclampsia, and controls were normotensive with negative urine protein. Serum calcium and magnesium were measured to calculate the calcium-to-magnesium ratio.  Results: Fifty-two pregnant women were analyzed, including 26 with preeclampsia and 26 normotensive controls. Maternal age was similar between groups (28.96 ± 2.76 vs 29.54 ± 3.00 years, p=0.474), and gestational age did not differ (33.04 ± 2.16 vs 32.92 ± 3.01 weeks, p=0.874). Body mass index was higher in preeclampsia (28.57 ± 4.86 vs 24.27 ± 4.38 kg/m², p=0.002). Systolic and diastolic pressures were higher in preeclampsia (p<0.001 each). Serum calcium, magnesium, and the calcium to magnesium ratio were lower in preeclampsia (p<0.001, p=0.015, and p=0.002), supporting altered mineral balance in affected pregnancies. Conclusion:  Women with preeclampsia showed lower serum calcium, serum magnesium, and a reduced calcium to magnesium ratio compared with controls. Consequently, a low serum calcium to magnesium ratio could be a risk factor for preeclampsia.