Magnesium Oxide use while Breastfeeding
Drugs containing Magnesium Oxide: Prepopik, Mag-Ox 400, Mag-Ox, Mag-Oxide, Phillips' Cramp-free, Uro-Mag, MagGel, Mag-Caps, Mag-200
Magnesium Oxide Levels and Effects while Breastfeeding
Summary of Use during Lactation
No information is available on the clinical use of magnesium oxide during breastfeeding. However, other magnesium salts have been studied. A study on the use of magnesium hydroxide during breastfeeding found no adverse reactions in breastfed infants. Intravenous magnesium increases milk magnesium concentrations only slightly. Oral absorption of magnesium by the infant is poor, so maternal magnesium hydroxide is not expected to affect the breastfed infant's serum magnesium. Magnesium oxide can be taken during breastfeeding and no special precautions are required.
Maternal Levels. Ten women with pre-eclampsia were given 4 grams of magnesium sulfate intravenously followed by 1 gram per hour until 24 hours after delivery. While the average serum magnesium was 35.5 mg/L in treated women compared to 18.2 mg/L in 5 untreated controls, colostrum magnesium levels at the time of discontinuation of the infusion was 64 mg/L in treated women and 48 mg/L in the controls. By 48 hours after discontinuation, colostrum magnesium levels were only slightly above control values and by 72 hours they were virtually identical to controls.
Infant Levels. Relevant published information was not found as of the revision date.
Effects in Breastfed Infants
Fifty mothers who were in the first day postpartum received 15 mL of either mineral oil or an emulsion of mineral oil and magnesium hydroxide equivalent to 900 mg of magnesium hydroxide, although the exact number who received each product was not stated. Additional doses were given on subsequent days if needed. None of the breastfed infants were noted to have any markedly abnormal stools, but all of the infants also received supplemental feedings.
Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.
Alternate Drugs to Consider
1. Cruikshank DP, Varner MW, Pitkin RM. Breast milk magnesium and calcium concentrations following magnesium sulfate treatment. Am J Obstet Gynecol. 1982;143:685-8. PMID: 7091241
2. Baldwin WF. Clinical study of senna administration to nursing mothers.:assessment of effects on infant bowel habits. Can Med Assoc J. 1963;89:566-7. PMID: 14045350
Magnesium Oxide Identification
CAS Registry Number
LactMed Record Number
Last Revision Date
Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.