<qa>  What is the exact MgSO4 protocol used?The study will be a multicenter, randomized, controlled, clinical trial comparing the anti-seizure effect of parenteral andor oral labetalol n 4000 versus parenteral intravenous or intramuscular magnesium sulfate n 4000 with mild or severe preeclampsia who are deemed to be at sufficient risk to warrant seizure prophylaxis with magnesium sulfate. This allows for a 2 lost to follow-up rate. Patients receiving labetalol will either be given a 20 mg intravenous loading dose IV followed by a 200 mg oral dose every 6 hours from the time of inclusion in the study until 24 hours postpartum, or will receive only the 200 mg oral dose every 6 hours from inclusion. Whether or not an IV dose is necessary will be decided by the clinician in charge. Only patients thought to be at sufficient risk to warrant immediate anti-hypertensive therapy will receive the initial IV dose. Patients randomized to the magnesium sulfate group will receive intravenous magnesium sulfate as a 4 or 6 gram loading dose over 20 minutes followed by a 1 or 2 gh continuous infusion until 24 hours postpartum. The exact MgSO4 protocol used will be determined by the protocol in use at each institution. We have previously shown in the Nimodipine study as have others with the MAGPIE study that there is no difference in seizure rate between the 1ghr and 2ghr protocols. Patients on the labetalol arm of the study who convulse will be treated with magnesium sulfate. Patients on the magnesium sulfate arm will continue to receive magnesium sulfate. All patients who convulse will be managed per the units standard protocol for eclampsia treatment. 