Associated Factors of Subtherapeutic Serum Magnesium Level for Prevention of Eclampsia in Term Pregnant Women with Severe Pre-eclampsia

Vitaya Titapant; Kingkaew Mingsuttiporn

doi:10.33192/Smj.2020.21

Authors

Vitaya Titapant Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700
Kingkaew Mingsuttiporn Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 http://orcid.org/0000-0001-5956-8109

DOI:

https://doi.org/10.33192/Smj.2020.21

Keywords:

Pre-eclampsia; magnesium sulfate; therapeutic level; associated factors

Abstract

Objective: To investigate the factors associated with subtherapeutic serum magnesium levels in order to prevent eclampsia in term pregnant women with severe pre-eclampsia.
Methods: This case-control study included 200 term pregnant women with severe pre-eclampsia who received magnesium sulfate for eclampsia prophylaxis. These patients were randomly allocated into case and control groups. Experimental cases included 100 women whose serum magnesium level did not reach the therapeutic level (<4.8 mg/dL) at 2 hours after initial administration, whereas the controls were 100 women whose serum magnesium levels reached therapeutic levels (4.8-8.4 mg/dL). Data from the medical records, including baseline characteristics, sign and symptoms, laboratory findings and pregnancy outcomes, were extracted for univariate and multivariate analyses.
Results: Only two factors, pre-pregnancy body mass index (BMI) and serum creatinine level, showed significant differences between the two groups. Pre-pregnancy BMI greater than 25 kg/m² increased the risk of subtherapeutic serum magnesium level by 56% compared with normal pre-pregnancy BMI (adjusted OR 1.56, p=0.019), whereas pre-pregnancy BMI less than 18 kg/m² decreased the risk by 80% (adjusted OR 0.2, p=0.02). Also, serum creatinine levels greater than 0.9 mg/dl decreased the risk by 98.7% (adjusted OR 0.013, p<0.001). No significant difference in pregnancy outcomes was noted in either group.
Conclusion: Pre-pregnancy BMI greater than 25 kg/m² increased the risk, whereas pre-pregnancy BMI less than 18 kg/m² decreased the risk of subtherapeutic serum magnesium levels. A serum creatinine level greater than 0.9 mg/dl was another factor that decreased the risk.

References

1. Cunningham FG, Leveno KJ, Bloom SL, Hauth JC, Rose DJ, Spong CY, editor. Williams’s Obstetrics. 23rd ed. New York: McGraw Hill; 2012.p.706.
2. Taweesul P, Tannirandorn Y. Clinical and laboratory parameters associated with eclampsia in Thai Pregnant Women. J Med Assoc Thai 2014;97:139-46.
3. Sibai BM, Lipshitz J, Anderson GD, Dilts PV Jr. Reassessment of intravenous MgSO4 therapy in preeclampsia-eclampsia. Obstel Gynecol 1981;57:199-202.
4. Sibai BM. Diagnosis and management of gestational hypertension and preeclampsia. Obstet Gynecol 2003;102:181-2.
5. JamiluTukur. The use of magnesium sulphate for the treatment of severe pre-eclampsia and eclampsia. Ann Afr Med 2009;8:76-80.
6. Zuspan FP. Problems encountered in the treatment of pregnancy-induced hypertension.A point of review. Am J Obstet Gynecol 1978;131:591-7.
7. Pritchard JA, Cunningham FG, Pritchard SA. The Parkland memorial hospital protocol for treatment of eclampsia: evaluation of 245 cases. Am J Obstet Gynecol 1984;148:951-63.
8. Smith JM, Lowe RF, Fullerton J, Currie SM, Harris L, Felker-Kantor E. An integrative review of the side effects related to the use of magnesium sulfate for pre-eclampsia and eclampsia management. BMC Pregnancy Childbirth 2013;13:34.
9. Tudela CM, McIntire DD, Alexander JM. Effect of maternal body mass index on serum magnesium levels given for seizure prophylaxis. Obstet Gynecol 2013;121:314-20.
10. Yu AS. Evolving concepts in epithelial magnesium transport. Curr Opin Nephrol Hypertens 2001;10:649-53.
11. Mann CK, Yoe JH. Spectrophotometric determination of magnesium with sodium 1-azo-2-hydroxy-3-(2, 4-dimethyl-carboxanilido)-napthalene-1’-(2-hydroxybenzene-5-sulfonate) Anal Chem 1956;28:202-5.
12. Kanagal DV, Rajesh A, Rao K, Devi UH, Shetty H, Kumari S, et al. Levels of serum calcium and magnesium in pre-eclamptic and normal pregnancy: a study from coastal India. J Clin Diagn Res 2014;8:OC01-4.
13. Swaminathan R. Magnesium metabolism and its disorders. Clin Biochem Rev 2003;24:47-66.
14. Saris NE, Mervaala E, Karppanen H, Khawaja JA, Lewenstam A. Magnesium.an update on physiological, clinical and analytical aspects. Clin Chim Acta 2000;294:1-26.
15. Kroll MH, Elin RJ. Relationships between magnesium and protein concentrations in serum. Clin Chem 1985;31:244-6.
16. Ephraim RK, Osakunor DN, Denkyira SW, Eshun H, Amoah S, Anto EO. Serum calcium and magnesium levels in women presenting with pre-eclampsia and pregnancy-induced hypertension: a case-control study in the Cape Coast metropolis, Ghana. BMC Pregnancy Childbirth 2014;14:390.