Intravenous and intramuscular magnesium sulphate regimens in severe pre-eclampsia

Patients with severe pre-eclampsia were randomised to receive magnesium sulphate according to an intramuscular (IM) (N = 9) or an intravenous (i.v.) (N = 8) regimen. The IM regimen consisted of a loading dose of 14 g (4 g i.v. and 10 g IM) followed by 5 g 4-hourly. Patients given the IV regimen received a 6 g i.v. loading dose followed by a maintenance infusion of 2 g/h. Clinical outcome, laboratory parameters and serum magnesium levels were recorded for both groups. There were no significant differences between groups with regard to clinical outcome of either mother or child. Similar average serum magnesium concentrations were produced by the regimens the only significant difference was that fluctuations in magnesium levels were greater with the IM than the i.v. regimen. None of the patients had seizures despite levels mostly below 2 mmol/l.