Decreased Serum Magnesium Level among Nigerian Women with Late Onset Pre-eclampsia

Background: Pre-eclampsia is a common medical complication of pregnancy associated with increased maternal and perinatal mortality and morbidity. Its etiology is unknown, although several evidences indicate that deficiency of various nutritional elements might play important role.

Aims: To compare the serum magnesium levels in a group of pre-eclamptic and normotensive pregnant Nigerian women in Jos, Nigeria.

Study Design: This was a descriptive cross-sectional study.

Place and Duration of Study: Department of Obstetrics and Gynaecology, Jos University Teaching Hospital, Jos, between May 2011 and April, 2012.

Methodology: We included 50 pre-eclamptic patients and 50 controls in the study. A structured questionnaire was administered directly on each subject. For each recruited pre-eclamptic patient, the next eligible normotensive patient matched for age, occupation, educational status, socioeconomic status, parity and gestational age was recruited as control. Venous blood samples were collected from pre-eclamptic and normotensive pregnant women. The sera from the samples were analyzed for magnesium using a photometric colorimetric analyzer (Diagnosticum Zrt; Budapest). The data were analyzed using Epi info 3.5.1 software (CDC, Atlanta Georgia, USA). Tests of associations were done using Student's t-test and chi square test. P value < 0.05 was considered statistically significant.

Results: Mean serum magnesium level in pre-eclamptic women was 0.89±0.10 mmol/l compared to 1.07±0.12 mmol/l in the normotensive pregnant women (p = 0.001).The range of serum magnesium in the pre-eclamptics was 0.73 ̶ 0.96 mmol/l while that in normotensive pregnancies was 0.95 – 1.26 mmol/l. In patients with mild pre-eclampsia, the mean serum magnesium was 0.93±0.09 mmol/l while it was 0.81±0.08 mmol/l in those with severe pre-eclampsia (p < 0.0001). Also there was an inverse relationship between serum magnesium and systolic blood pressure (r = -0.404, p = 0.004) as well as serum magnesium and diastolic blood pressure (r = -0.462, p = 0.001).

Conclusion: Serum magnesium level in pre-eclamptics was significantly lower than those in normotensive pregnant women. This finding supports the hypothesis that hypomagnesaemia may be a contributor to the etiology of pre-eclampsia. Introduction of magnesium supplementation in diet may help reduce the incidence of pre-eclampsia in at risk women.