Factors associated with pharmacologic serum concentration of magnesium and corresponding obstetric outcomes among women with severe preeclampsia at Iringa regional referral hospital.

Abstract

Introduction: Severe pre-eclampsia is managed by using magnesium sulphate (MgSO4) to prevent its progression to eclampsia, with a success rate of more than 50%. Blood levels of Magnesium following initiation of the MgSO4 are key in ensuring effective management of severe pre-eclampsia while preventing toxicity.

Objective: This study aimed at establishing reliable data pertaining to factors influencing the pharmacologic serum concentration of magnesium and their association to obstetric outcomes.

Methods: This analytical cross-sectional study was carried out at the Iringa regional referral hospital for six months from November 2023 to April 2024. Due to the limited cases and study duration, a purposeful sampling technique was used to recruit 121 women with severe pre-eclampsia. Recruited women were tested for serum magnesium at admission, 4 and 12 hours after initial administration of MgSO4. IBM SPSS version 29 was used for analysis, where continuous variables were summarized using the median and interquartile range, while categorical variables were summarized using frequency and percentages. The associations between variables were determined using chi-square tests, univariate, and multivariable logistic regression models. A p value<0.05 was considered statistically significant.

Results: he proportion of women who attained none-therapeutic serum Mg at 4 hours was 38.8%, with a median of 1.9±1.02 IQR Mmol/L. Multivariable logistic regression showed that; low serum Mg at admission [p<0.001, OR= 9.17, 95% CI (3.07- 27.37)], high creatinine level [p = 0.012, OR= 4.49, 95% CI (1.38- 14.6)], overweight [p = 0.002, OR= 5.52, 95% CI (1.83- 16.68)] and proteinuria +++ [p-value = 0.004, OR= 7.13, 95% CI (1.84- 26.86)] were significantly associated with subtherapeutic level. After adjusting for other factors, it was found that subtherapeutic levels [p<0.001, OR=25.44(5.73-112.90)], elevated creatinine [p=0.040, OR=3.59(1.66-12.15)], and reduced urine output [p=0.001, OR=6.69(2.15-20.90)] were significant predictors of adverse maternal outcomes.

Conclusion: A large proportion of women with severe pre-eclampsia were observed to have low serum magnesium concentration at admission prior to the administration of the loading dose of MgSO4. Subtherapeutic serum concentration of magnesium is associated with unfavorable obstetric outcomes.