Magnesium sulfate is sometimes used as a tocolytic medicine to slow uterine contractions during preterm labor. But studies show it does not stop preterm labor and it may cause complications for both mother and baby.1
This medicine is thought to affect the action of calcium in the body, and calcium must be present for the muscles of the uterus to contract.
Magnesium sulfate may be used to stop preterm labor when:
If preterm labor is likely to lead to preterm delivery, magnesium sulfate may be used to reduce the risk of cerebral palsy in the premature newborn.2More research is needed to find out how well this works.3
Common side effects of this medicine include:
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
In rare cases, symptoms of magnesium toxicity (nausea, muscle weakness, loss of reflexes) occur during magnesium sulfate treatment. The medicine calcium gluconate is given to treat the problem.
Mothers on magnesium sulfate are closely monitored. Blood pressure and pulse are checked about every 30 minutes for at least the first few hours of treatment.
- Grimes DA, Nanda K (2006). Magnesium sulfate tocolysis: Time to quit. Obstetrics and Gynecology, 108(4): 986–989.
- Rouse DJ, et al. (2008). A randomized, controlled trial of magnesium sulfate for the prevention of cerebral palsy. New England Journal of Medicine, 359(9): 895–905.
- American College of Obstetricians and Gynecologists (2010). Magnesium sulfate before anticipated preterm birth for neuroprotection. ACOG Committee Opinion No. 455. Obstetrics and Gynecology, 115(3): 669–671.
- Haas DM (2010). Preterm birth, search date June 2009. Online version of BMJ Clinical Evidence: http://www.clinicalevidence.com.
Last Revised: January 10, 2011
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