Is Milk of Magnesia Safe During Pregnancy

Status

caution Last reviewed: 2026-05-16 · Confidence: low

Reason

Limited pregnancy data for OTC use; use only as directed and ask your OB/GYN or prescriber.

Drug Information

Brand Name
Milk of Magnesia
Generic Name
magnesium hydroxide
Drug Class
osmotic laxative / antacid
FDA Category
unknown
Rx Status
OTC

Safe Amount

Dosage must be determined by your provider based on individual risk/benefit. Follow the product label; do not exceed OTC directions.

Effects

Pregnancy
OTC use is common, but pregnancy-specific safety data are limited; pregnancy dosing limits may apply.
Mother
May cause diarrhea, cramping, dehydration, and electrolyte changes; kidney disease can raise magnesium risk.
Baby
High or prolonged magnesium exposure may affect the baby’s magnesium levels; OTC doses are not well studied in pregnancy.

Trimester Notes

1st Trimester
Limited official pregnancy data. Ask your provider before use, especially if symptoms are ongoing.
2nd Trimester
Use only as directed. Do not exceed label directions without medical advice.
3rd Trimester
Use only if your provider says it is needed. Prolonged or high-dose magnesium exposure can be a concern near delivery.

Conditions & Warnings

  • Consult OB/GYN or prescriber
  • Pregnancy dosing limits may apply
  • Avoid prolonged or high-dose use unless your provider approves
  • Use extra caution if you have kidney disease

Alternatives

  • Polyethylene glycol 3350 (ask your provider)
  • Bulk-forming fiber products
  • Docusate sodium (ask your provider)
  • Diet changes: fluids, fiber, and activity if approved by your clinician

References

  • FDA/DailyMed
    https://www.accessdata.fda.gov/drugsatfda_docs/label/2009/022456lbl.pdf
  • NHS
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