Magnesium Sulfate Administration in Pregnant Women

Primary Indications and Clinical Scenarios

The American College of Obstetricians and Gynecologists recommends magnesium sulfate for pregnant women with severe preeclampsia who have at least one clinical sign of seriousness to prevent eclamptic seizures, and in all cases of eclampsia for seizure control, with a strength of evidence based on high-quality trials 1, 2
Magnesium sulfate is indicated for severe preeclampsia with clinical signs of seriousness, including blood pressure ≥160/110 mmHg with significant proteinuria or moderate hypertension with proteinuria and neurological symptoms, according to the American College of Obstetricians and Gynecologists 3
The American College of Obstetricians and Gynecologists recommends magnesium sulfate as the most effective agent for controlling eclamptic seizures, superior to phenytoin and diazepam, with a high strength of evidence 4, 2

The standard loading dose of magnesium sulfate is 4-6 grams IV over 20-30 minutes, followed by a maintenance infusion of 1-2 grams per hour by continuous IV infusion, as recommended by the American College of Obstetricians and Gynecologists 5, 3
For patients with BMI ≥25 kg/m², a higher maintenance dose of 2 grams per hour is recommended to achieve therapeutic levels, according to the American College of Obstetricians and Gynecologists 5

The American College of Obstetricians and Gynecologists recommends that patellar reflexes be present before administration, and that respiratory rate and urine output be monitored continuously during administration, with a strength of evidence based on high-quality trials 5
Oxygen saturation should be maintained above 90% during administration, as recommended by the American College of Obstetricians and Gynecologists 5

The American College of Obstetricians and Gynecologists recommends that magnesium sulfate never be combined with calcium channel blockers, as this can cause severe hypotension and myocardial depression, with a high strength of evidence 5, 2, 3
Fluid intake should be limited to 60-80 mL/hour to avoid pulmonary edema, as recommended by the American College of Obstetricians and Gynecologists 5, 3

For overweight patients (BMI ≥25 kg/m²), the American College of Obstetricians and Gynecologists recommends starting maintenance at 2 grams per hour rather than 1 gram per hour, with a strength of evidence based on high-quality trials 5