PLASMA AND RED-CELL MAGNESIUM LEVELS IN BLACK-AFRICAN WOMEN WITH HYPERTENSIVE DISORDERS OF PREGNANCY

Objective: To measure plasma and red cell magnesium levels in black Af rican women with hypertensive disorders of pregnancy. Methods: Plasma and red cell magnesium levels were analyzed using atomic absorption sp ectrophotometer in 27 patients presenting with severe hypertension in pregnancy, 27 patients with mild hypertension in pregnancy, and 27 hea lthy normotensive pregnant women. Results: There were no significant d ifferences in plasma magnesium concentrations between the hypertensive groups compared to the normotensive group [mild vs. normotensive (0.8 2 +/- 0.03 vs. 0.84 +/- 0.03 mmol/L; P = 0.12); severe hypertension vs . normotensive (0.80 +/- 0.03 vs. 0.84 +/- 0.03 mmol/L; p = 0.15)]. Th ere were not statistical differences in plasma magnesium levels betwee n the hypertensive groups. There was a significant difference in the r ed cell magnesium concentrations between normotensive women and those with mild hypertension (2.3 +/- 0.3 vs. 2.6 +/- 0.5 mmol/L; P < 0.05) and those with severe hypertension in pregnancy (1.35 +/- 0.3 vs. 2.6 +/- 0.5 mmol/L; P < 0.001). Similarly, there was a significant differe nce between the mild and the severe hypertensive groups (2.3 +/- 0.3 v s. 1.35 +/- 0.3 mmol/L; P < 0.001). In addition, the red cell magnesiu m levels were also decreased after 36 weeks' gestation compared to bef ore 36 weeks in the mild group (2.0 +/- 0.07 vs. 2.6 +/- 0.35 mmol/L; P < 0.05) and in the severe group (1.18 +/- 0.08 vs. 1.30 +/- 0.06 mmo l/L; P < 0.001). Conclusion: Lowered red cell magnesium concentrations may be a contributory factor in the development of hypertensive disor ders of pregnancy.