Hypertensive disorders of pregnancy are important causes of morbidity and mortality. The levels of calcium (Ca 2+) and magnesium (Mg 2+) in pregnancy may implicate their possible role in pregnancy-induced hypertension. This study assessed serum Ca 2+ and Mg 2+ levels in women with PIH (pregnancy-induced hypertension) and PE (pre-eclampsia), compared to that in normal pregnancy.
This case–control study was conducted on 380 pregnant women (≥20 weeks gestation) receiving antenatal care at three hospitals in the Cape Coast metropolis, Ghana. This comprised 120 women with PIH, 100 women with PE and 160 healthy, age-matched pregnant women (controls). Demographic, anthropometric, clinical and obstetric data were gathered using an interview-based questionnaire. Venous blood samples were drawn for the estimation of calcium and magnesium.
Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly raised in women with PIH ( p < 0.0001) and PE ( p < 0.0001). Women with hypertensive disorders (PE and PIH) had significantly lower serum calcium and magnesium levels than those in the control group ( p < 0.0001 each). Of those with PIH, SBP correlated positively with BMI (r = 0.575, p < 0.01) and Ca 2+ correlated positively with Mg 2+ (r = 0.494, p < 0.01). This was similar amongst the PE group for SBP and BMI as well as for Ca 2+and Mg 2+ but was not significant. Multivariate analysis showed that women aged ≥40 years were at a significant risk of developing PIH (OR = 2.14, p = 0.000).