Is it safe for a pregnant woman to take 250 mg of vitamin B6?

Vitamin B6 at 250 mg Daily in Pregnancy: Safety Concerns

A dose of 250 mg of vitamin B6 daily during pregnancy significantly exceeds established safety thresholds and poses substantial risk of maternal neurotoxicity, with emerging evidence suggesting potential harm to fetal development—this dose should be avoided.

Critical Safety Thresholds

The dose in question (250 mg/day) is dangerously high when compared to established limits:

• The European Food Safety Authority's upper tolerable limit is 100 mg/day for adults, and even this level has been associated with toxicity in susceptible individuals 1
• Toxicity has been documented with prolonged intake of just 100 mg/day 1
• The recommended daily intake for adults is only 1.3-1.7 mg/day 1, 2
• Even "low-dose" supplementation of 6-40 mg/day has caused toxicity in case reports 1

Your proposed dose of 250 mg/day is 2.5 times the established upper safety limit and over 150 times the recommended daily intake.

Documented Maternal Risks at High Doses

Neurological Toxicity

Chronic intake exceeding 100 mg/day causes sensory neuropathy 2, and your dose substantially exceeds this threshold:

• Plasma PLP levels above 100 nmol/L (25 μg/L) are associated with neurotoxicity 3
• In a systematic review, 164 out of 1,226 women taking excessive vitamin B6 experienced neurological symptoms including burning, tingling, paresthesia, ataxia, or perioral numbness 4
• Neurological damage has been reported at doses exceeding 500 mg/day, but even 50-100 mg/day cannot be regarded as without hazard 5

Recovery from Toxicity

If toxicity develops, the prognosis is concerning:

• Grade 3-4 neurological impairments require longer recovery periods than grade 1-2 symptoms 1
• Some deficits may be permanent if caused during development 6

Emerging Evidence of Fetal Risk

While older data suggested relative safety, the most recent systematic review (2024) raises serious concerns:

• Out of 245 women taking excessive vitamin B6, four experienced miscarriages and one had intrauterine fetal demise 4
• Overconsumption has the potential to impact nerve function during the critical first trimester of embryonic development and might result in adverse outcomes including miscarriage, intrauterine fetal demise, and congenital abnormalities 4
• Large doses of vitamin B6 can have adverse effects on proprioceptive neuron function, and these deficits may be permanent if caused during development 6
• The effect of large doses of vitamin B6 on developing human fetuses is currently unknown, and ingestion should be viewed with caution by pregnant women 6

This represents a significant shift from earlier reassuring data 7, with the most recent and comprehensive evidence suggesting potential harm.

Appropriate Dosing for Pregnancy-Related Nausea

If vitamin B6 is being considered for nausea and vomiting of pregnancy, the evidence-based approach is dramatically different:

• Start with 10 mg orally every 8 hours for mild to moderate symptoms 2
• Increase to 25 mg every 8 hours if inadequate response after 24-48 hours 2
• Maximum recommended dose is 25 mg three times daily (75 mg total daily) 2
• Add doxylamine to vitamin B6 for combination therapy if monotherapy is insufficient 2

Even the maximum therapeutic dose for nausea (75 mg/day) is less than one-third of your proposed 250 mg dose.

Clinical Context from Other Conditions

The only scenario where higher doses approach this range is tuberculosis treatment:

• Pyridoxine supplementation at 25-50 mg/day is recommended for patients taking tuberculosis medications, increased to 100 mg/day only if peripheral neuropathy develops 1
• Pyridoxine supplementation (25 mg/day) is recommended during pregnancy for women taking isoniazid 8

Even in this specific medical context, doses remain well below 250 mg/day.

Immediate Recommendations

Do not take 250 mg of vitamin B6 daily during pregnancy. This dose:

• Exceeds all established safety guidelines by a factor of 2.5 or more
• Carries documented risk of maternal neurotoxicity
• Has emerging evidence of potential fetal harm based on the most recent systematic review
• Far exceeds any therapeutic dose recommended for pregnancy-related conditions

If vitamin B6 supplementation is needed for nausea, follow the evidence-based algorithm starting at 10-25 mg three times daily (maximum 75 mg/day total) 2.

If already taking this dose, immediate discontinuation of all pyridoxine supplementation is the primary treatment for vitamin B6 toxicity 1, and consultation with an obstetrician is essential.