Background and Objective: Pre-eclampsia is one of the pregnancy complications that can result in maternal and neonatal morbidity and mortality. Magnesium sulfate (MgSO4) is one of the effective drugs to prevent and stop seizures in pre-eclampsia and eclampsia.  This study aimed to investigate the characteristics of patients with pre-eclampsia and eclampsia and serum magnesium levels during MgSO4 therapy.Methods: A cross-sectional study design used secondary data from the Emergency Maternity Room of Prof. Dr. I.G.N.G. Ngoerah Hospital. The samples were all superimposed pre-eclampsia, severe pre-eclampsia, and eclampsia cases in 2019. We collected and analyzed characteristic and laboratory data, including the MgSO4 serum levels of the patients. Participants' baseline characteristics (CBC, blood chemistry, and MgSO4) and their diagnosis were compared using the chi-square test for categorical data and the independent t-test for numerical data.Results: The patients with severe pre-eclampsia were 183 patients, superimposed pre-eclampsia were 41 patients, and eclampsia 15 patients. Age <35 years old was the most influential characteristic variable in superimposed pre-eclampsia (adjusted odds ratio (aOR)=0.166, P<0,001, 95%CI=0.082-0.336) and severe pre-eclampsia (aOR=3.011, p<0,001, 95%CI=1.662-5.455). Hospital referrals were the most influential characteristic variable in eclampsia (aOR=3.653, P=0.016, 95%CI=1.273-10.486). The administration of MgSO4 was significant with severe pre-eclampsia (P<0.001). The highest serum magnesium occurred 6 hours before MgSO4 administration (3.97 ± 1.28 mg/dL).Conclusion: Patients with superimposed pre-eclampsia, severe pre-eclampsia, and eclampsia conditions have various characteristics associated with each state. During the use of MgSO4, there was a significant association between serum magnesium levels and the therapeutic target levels.