A Comparison Study of Serum Calcium Levels in Normal Pregnancy and Pregnancy-Associated Hypertension

Background: Hypertensive disorders of pregnancy, including gestational hypertension and preeclampsia, are major causes of maternal and perinatal morbidity and mortality. Altered calcium metabolism has been implicated in pregnancy-associated hypertension, but evidence regarding maternal serum calcium and disease severity remains inconsistent. This study compared serum calcium levels between normotensive pregnant women and women with pregnancy-associated hypertension and assessed associations with clinical severity. Methods: This hospital-based comparative analytical study included 200 pregnant women beyond 20 weeks of gestation at the Department of Obstetrics and Gynecology, Government Mohan Kumaramangalam Medical College and Hospital, Salem, Tamil Nadu. One hundred women with pregnancy-associated hypertension were compared with 100 normotensive controls. Serum calcium was estimated using standard laboratory procedures. Results: Mean serum calcium was lower in women with pregnancy-associated hypertension than in normotensive women (8.74 vs. 9.24 mg/dL; p<0.005). Cases had higher BMI and differed from controls in age, gestational age, and parity. Serum calcium showed significant inverse correlations with systolic blood pressure (r=−0.48, p<0.001), diastolic blood pressure (r=−0.41, p<0.001), and proteinuria (r=−0.35, p=0.002). Conclusion: Serum calcium was lower in women with pregnancy-associated hypertension and was inversely associated with blood pressure and proteinuria. Serum calcium may have potential as an inexpensive biochemical marker of disease severity; larger prospective multicenter studies are needed to confirm these findings.