A retrospective review of the risk factors affecting the therapeutic serum concentrations of magnesium sulfate in pre-eclamptic patients

What is known and objective: To identify factors that may affect the therapeutic serum magnesium levels after intravenous administration for seizure prophylaxis in pre-eclamptic patients.

Methods: One hundred and two women with PE with severe features were identified categorized into two groups: subtherapeutic and therapeutic group. Multivariate logistic regression analysis and receiver operation characteristic curve analysis were conducted for the risk factors influencing the serum magnesium concentration.

Results: Among 102 eligible patients, 63 (62%) patients did not attain ideal therapeutic serum magnesium levels. Those patients had elevated albumin levels (p < 0.05), higher creatinine clearance (Ccr) (p < 0.001), and higher body mass index (BMI) (p < 0.001). Logistic regression analysis identified BMI and Ccr as independent risk factors for subtherapeutic serum magnesium concentration (p < 0.05). Receiver operating characteristic (ROC) curve analysis revealed a greater area under the curve for BMI than for Ccr in predicting subtherapeutic serum magnesium levels (0.787 vs. 0.774).

What is new and conclusion: Maternal body weight and renal function were independent risk factors for subtherapeutic serum magnesium concentration in the early stage after administration.