Retrospective–Prospective Observational Study of Serum Magnesium Level Dynamics and Their Correction in Physiological and Complicated Pregnancies

Abstract

Background and Aims Magnesium is an essential micronutrient involved in numerous biochemical and physiological processes during pregnancy. The aim of this study was to evaluate serum magnesium level dynamics during physiological and complicated pregnancies and to assess the effectiveness of magnesium deficiency correction. Methods A retrospective–prospective observational cohort study was conducted between 2020 and 2025, including 233 pregnant women. Serum magnesium levels were measured in the first and third trimesters. Participants were divided into physiological (n = 110) and complicated pregnancy (n = 123) groups. Magnesium status was classified as deficiency (< 0.72 mmol/L), insufficiency (0.72–0.80 mmol/L), and normal (> 0.80 mmol/L). Oral magnesium lactate with pyridoxine was administered in cases of deficiency. Statistical analysis was performed using SPSS software with a significance level of p < 0.05 (two‐sided). Effect size was assessed using Cohen’s d. Results In physiological pregnancies, no statistically significant changes in serum magnesium levels were observed between trimesters (p > 0.05). In complicated pregnancies, a downward trend in magnesium levels was observed, reaching statistical significance in one subgroup (p = 0.043; d = 0.41). Patients with baseline deficiency or insufficiency did not achieve normalization despite therapy. Differences between treated and untreated groups were limited and inconsistent. Conclusion Serum magnesium levels remain stable during physiological pregnancy but tend to decrease in complicated pregnancies. Standard oral magnesium supplementation demonstrates limited effectiveness in restoring normal serum levels, highlighting the need for further research and individualized therapeutic strategies.