Clinical significance of low serum magnesium in pregnant women attending the University of Benin Teaching Hospital

Objective: Magnesium level is known to decline during pregnancy. A suggested role for magnesium deficiency in conditions like pre-eclampsia and pre-term birth has prompted studies with conflicting evidence. The primary objective of this study was to determine the prevalence of hypomagnesemia in pregnancy, while the secondary objectives attempted to define maternal and fetal outcome due to hypomagnesemia. Subjects and Methods: A pilot study was performed to determine the mean serum magnesium level for the population of female patients attending the University of Benin Teaching Hospital. The result of the pregnant population in the pilot study was used as a reference for hypomagnesemia in this study. Thereafter, a prospective cohort study of antenatal women recruited in the second trimester and followed-up till delivery and 1 week post-partum was done. Serum magnesium estimates were done with samples collected at recruitment and delivery. The magnesium levels determined at recruitment were used to divide the subjects into two groups of hypomagnesemic and normomagnesemic patients. Their sociodemographic and clinical characteristics were used to generate a database for analysis. Results: The prevalence of magnesium deficiency was 16.25%. Hypomagnesemia was significantly correlated with the occurrence of pre-eclampsia ( P = 0.011), leg cramps ( P = 0.000) and pre-term birth ( P = 0.030). A logistic regression analysis showed that hypomagnesemia had an Odds ratio of 22 for pre-eclampsia. There was no maternal mortality or early neonatal death. Conclusion: Pre-eclampsia and pre-term birth are associated with hypomagnesemia in pregnancy; hence, magnesium supplementation or magnesium-rich diet consisting of green leafy vegetables, soy milk and legumes may improve outcome.