The clinical and biochemical effects of excess magnesium in the newborn

The effect of two regimens of magnesium sulfate therapy in the toxemic mother and her newborn is reviewed. When magnesium sulfate is given intramuscularly to the mother, the newborn is usually not compromised by excess magnesium but may be affected. If continuous intravenous infusion of magnesium sulfate is used and especially if given for more than 24 hours, one can anticipate a newborn manifesting all the signs of hypermagnesemia. Serum levels in the cord blood and serial samples of the newborn do not necessarily correlate with the clinical picture and may be of little diagnostic value. In contrast to the adult, the newborn does not excrete a magnesium load satisfactorily. Magnesium toxicity should be recognized and treated as outlined in the infant of a toxemic mother who has received a large dose or prolonged magnesium sulfate therapy.