Serum magnesium level at 24 to less than 37 weeks: a prospective COHORT study predicting spontaneous preterm delivery


  • Astha Department of Obstetrics and Gynaecology, Autonomous State Medical College, Firozabad, Uttar Pradesh, India
  • Divya Department of Obstetrics and Gynaecology, Autonomous State Medical College, Firozabad, Uttar Pradesh, India



Serum magnesium level, Preterm labour, Perinatal morbidity and mortality


Background: Preterm labour is a leading cause of perinatal morbidity and mortality. Out of various causes, many macronutrients and micronutrients are said to have a role in pathogenesis of preterm labour, one of them is magnesium. Magnesium inhibits myometrial contractions by antagonizing calcium mediated uterine contractions. With advancement of pregnancy serum magnesium levels falls causing hyper excitability of neuromuscular junction bringing in uterine hyperactivity. The study was aimed to measure and compare the level of serum magnesium in preterm labour and normal pregnancy and to find the association of serum magnesium level with preterm labour.

Methods: This cohort observational study was done in Department of Obstetrics and Gynaecology, King George's Medical University, Lucknow and eligible participants i.e., pregnant women with singleton gestation between 24 and <37 weeks of gestation were enrolled.112 women with preterm labour and 120 with no preterm labour were taken as study and control group respectively, serum magnesium level measured and followed till delivery.

Results: The study showed mean serum magnesium level was 1.79±0.22 mg/dl in study group as compare to 1.98±0.25 mg/dl in control group and the difference was statistically significant (p<0.001). The value of Serum Magnesium below 1.885 mg/dl had a sensitivity of 64.8% and specificity of 66.1%.

Conclusions: We can conclude that low serum magnesium is associated with preterm labour and serum magnesium estimation in pregnancy may be a valuable marker of predicting preterm labour.


Keirse MJ. New perspectives for the effective treatment of preterm labor. Am J Obstet Gynecol. 1995;173(2):618-28.

Behrman RE. Preterm Birth: Causes, Consequences, and Prevention. Butler AS, eds. Washington (DC): National Academies Press (US); 2007.

Hofman PL, Regan F, Jackson WE, Jefferies C, Knight DB, Robinson EM, Cutfield WS. Premature birth and later insulin resistance. N Engl J Med. 2004; 351(21):2179-86.

March of Dimes, Premature Birth. Available at: Accessed on 20 February 2023.

Preterm birth. Available at: news-room/fact-sheets/detail/preterm-birth. Accessed on 20 February 2023.

Monutquin JM, Carbol D, Fisk NM, MacLennan AH, Marsal K, Rabinovici J. Effectiveness and safety of the oxytocin antagonist atosiban versus beta-adrenergic agonists in the treatment of preterm labour. Br J Obstet Gynecol. 2001;108;(2):133-42.

Lumely J. Defining the problem: the epidemiology of preterm birth. Int J Obstet Gynecol. 2003;110(20):3-7.

Peacock JL, Bland JM, Anderson HR. Preterm delivery:effects of socioeconomic factors psychological stress, smoking, alcohol and caffeine. Br Med J. 1995;311(7004):531-6.

Whitney EN, Cataldo CB, Rolfes SR. 6th ed. Understanding Normal and Clinical Nutrition. Belmont: Wadsworth; 1996.

Okunade KS, Oluwole AA, Adegbesan-Omilabu MA. A Study on the Association between Low Maternal Serum Magnesium Level and Preterm Labour. Adv Med. 2014;2014:704.

Kamal S, Sharan A, Kumar U, Shahi SK. Serum magnesium level in preterm labour. Indian J Pathol Microbiol. 2003;46(2):271-3.

Begum A, Das T. Low Serum Magnesium in Preterm Labour. JBCPS. 2020;28(2):86-91.

Whitehead NS. The relationship of socioeconomic status to preterm contractions and preterm delivery. Matern Child Health J. 2012;16(8):1645-56.

Sharma A, Kharb S, Vineeta, Gulati N. Serum magnesium levels in preterm labour in relation to socioeconomic status. Indian J Clin Biochem. 1998; 13(2):123-5.

Girsen AI, Mayo JA, Carmichael SL, Phibbs CS, Shachar BZ, Stevenson DK, et al. March of Dimes Prematurity Research Center at Stanford University School of Medicine. Women's prepregnancy underweight as a risk factor for preterm birth: a retrospective study. BJOG. 2016;123(12):2001-7.

Salihu HM, Mbah AK, Alio AP, Clayton HB, Lynch O. Low pre-pregnancy body mass index and risk of medically indicated versus spontaneous preterm singleton birth. Eur J Obstet Gynecol Reprod Biol. 2009;144(2):119-23.

Uludağ EÜ, Gözükara IÖ, Kucur SK, Uluğ P, Özdeğirmenci Ö, Erkaya S. Maternal magnesium level effect on preterm labor treatment. J Matern Fetal Neonatal Med. 2014;27(14):1449-53.

Mahmoud SA, Saleh IM, Khalaf HH. The correlation between maternal hypomagnesemia and preterm labour. Int J Reprod Contracept Obstet Gynecol. 2016; 5(8):2571-5.

Marzieh L, Ghomian N, Dadgar S, Halimi F. Maternal Magnesium Level Effect on Preterm Labour Treatment. Int J Women Health Reprod Sci. 2018; 6(1):55-9.

Arikan GM, Panzitt T, Gücer F, Scholz HS, Reinisch S, Haas J. Course of maternal serum magnesium levels in low-risk gestations and in preterm labor and delivery. Fetal Diagn Ther. 1999;14(6):332-6.

Nestler A, Rylander R, Kolisek M, Nielsen T, Ödman N, Vormann J, Bullarbo M. Blood pressure in pregnancy and magnesium sensitive genes. Pregnancy Hypertens. 2014;4(1):41-5.

Spätling L, Disch G, Classen HG. Magnesium in pregnant women and the newborn. Magnes Res. 1989; 2(4):271-80.

Kawagoe Y, Sameshima H, Ikenoue T, Yasuhi I, Kawarabayashi T. Magnesium sulfate as a second-line tocolytic agent for preterm labor: a randomized controlled trial in Kyushu Island. J Pregnancy. 2011; 2011:965060.

Zarean E, Tarjan A. Effect of Magnesium Supplement on Pregnancy Outcomes: A Randomized Control Trial. Adv Biomed Res. 2017;6:109.






Original Research Articles