Magnesium Glycinate Safety in Pregnancy
Yes, pregnant women can safely take magnesium glycinate within the recommended daily allowance, as magnesium supplementation during pregnancy is both safe and beneficial for preventing complications such as preeclampsia, preterm birth, and leg cramps.
Recommended Daily Allowance and Safety Limits
- The RDA for magnesium in pregnant women is 320 mg/day from all sources (food + supplements) 1
- The tolerable upper intake level (UL) is 350 mg/day from supplements alone (exclusive of intake from food and water), meaning dietary magnesium does not count toward this limit 1
- Magnesium glycinate falls within the safe supplementation range when kept at or below 350 mg/day from supplement sources 1
Clinical Benefits During Pregnancy
- Oral magnesium supplementation (including magnesium bisglycinate/glycinate at 300 mg/day) significantly reduces pregnancy-induced leg cramps, with 86% of women experiencing ≥50% reduction in cramp frequency versus 60.5% with placebo 2
- Magnesium supplementation (200 mg effervescent magnesium plus 100 mg from multivitamin) reduces the frequency of intrauterine growth restriction, preterm labor, preeclampsia, and gestational diabetes compared to multivitamin alone 3
- The majority of pregnant women do not meet their increased magnesium needs through diet alone, with mean dietary intake only 35-58% of the RDA 4
Specific Guidance for Magnesium Glycinate
- Magnesium glycinate is a well-absorbed, chelated form of magnesium that was specifically studied and proven safe at 300 mg/day in pregnant women for leg cramp relief 2
- This form causes minimal gastrointestinal side effects (no significant difference in nausea or diarrhea compared to placebo) 2
- Women should be counseled to increase intake of magnesium-rich foods (nuts, seeds, beans, leafy greens) and/or supplement at safe levels 5
Important Distinctions: Oral vs. Intravenous Magnesium
- Oral magnesium glycinate for supplementation is completely different from IV magnesium sulfate used therapeutically for severe preeclampsia/eclampsia 6, 7, 8
- IV magnesium sulfate is a medical treatment requiring hospital monitoring, not a dietary supplement 6, 7
- The 350 mg/day upper limit applies only to oral supplementation; therapeutic IV magnesium sulfate uses gram-level doses under medical supervision 6, 7
Practical Dosing Strategy
- Stay within 300-350 mg/day of supplemental magnesium glycinate to remain safely below the UL 1, 2
- Account for magnesium content in prenatal vitamins (typically 100 mg or less) when calculating total supplemental intake 4
- Dietary magnesium from food does not count toward the 350 mg supplement limit 1