Is Magnesium Sulfate compatible with breastfeeding? Do we have alternatives for Magnesium Sulfate?

Magnesium Sulfate

November 27, 2016 (Very Low Risk)

Magnesium is a natural component of milk.
It is used in the treatment and prophylaxis of eclampsia and migraine (Pringsheim 2012), in hypomagnesemia, in certain arrhythmias and as an osmotic laxative.

Its concentration in milk is very stable and depends little on diet and other factors, including the administration of magnesium sulfate to the mother: the magnesium levels in milk of mothers treated with intravenous magnesium sulfate were 6.4 mg / L versus 4.8 mg / L in the untreated ones (Cruikshank 1982, Dorea 2000).

Its low oral bioavailability makes it difficult to pass to infant plasma from ingested breast milk (Morris 1987) and its use during lactation is considered safe (Idama 1998).

Delay in lactogenesis II (milk rise) has been observed in women treated with magnesium sulfate before or during labor to treat or prevent eclampsia (Haldeman 1993) as well as hypotonia in newborns, which could interfere with the adequate breast stimulation (Riaz 1998) but this can be counteracted by a strong maternal decision and effective support to the mother (Cordero 2012).

American Academy of Pediatrics: medication usually compatible with breastfeeding.
List of essential medicines WHO 2002: compatible with breastfeeding.


We do not have alternatives for Magnesium Sulfate since it is relatively safe.

Very Low Risk

Compatible. Not risky for breastfeeding or infant.

Low Risk

Moderately safe. Mild risk possible. Follow up recommended. Read the Comment.

High Risk

Poorly safe. Evaluate carefully. Use a safer alternative. Read the Comment.

Very High Risk

Not recommended. Cessation of breastfeeding or alternative.


  • Epsom Salts
  • Sal Amarum


  • μαγνήσιο θειικό (Greek)
  • Сульфат Магния (Cyrillic)
  • 硫酸マグネシウム (Japanese)
  • MgSO4,xH2O (Molecular formula)


  1. Dennis AT. Management of pre-eclampsia: issues for anaesthetists. Anaesthesia. 2012Abstract Full text (link to original source) Full text (in our servers)
  2. Pringsheim T, Davenport W, Mackie G, Worthington I, Aubé M, Christie SN, Gladstone J, Becker WJ; Canadian Headache Society Prophylactic Guidelines Development Group. Canadian Headache Society guideline for migraine prophylaxis. Can J Neurol Sci. 2012Abstract Full text (in our servers)
  3. Cordero L, Valentine CJ, Samuels P, Giannone PJ, Nankervis CA. Breastfeeding in women with severe preeclampsia. Breastfeed Med. 2012Abstract
  4. WHO / UNICEF. BREASTFEEDING AND MATERNAL MEDICATION Recommendations for Drugs in the Eleventh WHO Model List of Essential Drugs. Department of Child and Adolescent Health and Development (WHO/UNICEF) 2002 Full text (link to original source) Full text (in our servers)
  5. AAP - American Academy of Pediatrics Committee on Drugs. Transfer of drugs and other chemicals into human milk. Pediatrics. 2001Abstract Full text (link to original source) Full text (in our servers)
  6. Dórea JG. Magnesium in human milk. J Am Coll Nutr. 2000Abstract
  7. Riaz M, Porat R, Brodsky NL, Hurt H. The effects of maternal magnesium sulfate treatment on newborns: a prospective controlled study. J Perinatol. 1998Abstract
  8. Hagemann TM. Gastrointestinal medications and breastfeeding. J Hum Lact. 1998Abstract
  9. Haldeman W. Can magnesium sulfate therapy impact lactogenesis? J Hum Lact. 1993Abstract
  10. Morris ME, LeRoy S, Sutton SC. Absorption of magnesium from orally administered magnesium sulfate in man. J Toxicol Clin Toxicol. 1987Abstract
  11. Cruikshank DP, Varner MW, Pitkin RM. Breast milk magnesium and calcium concentrations following magnesium sulfate treatment. Am J Obstet Gynecol. 1982Abstract