Quick answer
NIH says US obstetricians recommend vitamin B6 under a doctor's care for nausea and vomiting in pregnancy. The upper limit is 100 mg a day in the US and 12 mg in Europe, where it includes pregnancy. A Cochrane review of 41 trials found little information on harms. Ask your doctor before taking B6.1,2,3,4
Key facts
- NIH says the American College of Obstetricians and Gynecologists recommends vitamin B6 supplements under a doctor's care for nausea and vomiting in pregnancy.1,2
- NIH's professional sheet says pregnant women should consult a physician before taking a B6 supplement, because doses could approach the upper limit.2
- The US upper limit for vitamin B6 is 100 mg a day for adults and 80 mg for ages 14 to 18, counting food and supplements. Europe's is 12 mg a day for adults, including during pregnancy.2,3
- A Cochrane review of 41 trials with 5,449 women found little information on maternal and fetal adverse outcomes.4
- The label of a prescription tablet combining doxylamine and pyridoxine cites meta-analyses with no increased risk of malformations after first-trimester use.5
What do NIH and the obstetricians' college say about B6 in pregnancy?
NIH's consumer fact sheet says at least half of all women have nausea, vomiting or both in the first months of pregnancy, and that the American College of Obstetricians and Gynecologists, based on several studies, recommends taking vitamin B6 supplements under a doctor's care for it. The professional sheet adds that trial results have been mixed and that ACOG suggests adding doxylamine, an antihistamine, if B6 alone does not work.1,2
The professional sheet also makes a safety point in one line: before taking a vitamin B6 supplement, pregnant women should consult a physician because the doses recommended for nausea could approach the upper limit.2
What are the upper limits for vitamin B6 in pregnancy?
The US and European limits differ by a wide margin, and the gap is the main thing to understand. NIH's limit counts vitamin B6 from food, drinks and supplements together, and does not apply to people taking B6 for medical reasons under a doctor's care. The European Food Safety Authority set a much lower limit in 2023 that explicitly includes pregnant and lactating women.1,2,3
| Authority | Upper limit a day | Includes pregnancy |
|---|---|---|
| US Food and Nutrition Board (via NIH) | 100 mg (80 mg at ages 14 to 18) | Yes |
| European Food Safety Authority, 2023 | 12 mg | Yes |
The US upper limit for vitamin B6 is 100 mg a day for adults, counting food and supplements together. It is 80 mg for ages 14 to 18, 60 mg at 9 to 13, 40 mg at 4 to 8 and 30 mg at 1 to 3. In 2023 the European Food Safety Authority set a lower adult limit of 12 mg a day, including during pregnancy and breastfeeding. The US limit does not apply to people taking B6 for medical reasons under a doctor's care.1,2,3
What do reports say about birth defects?
Isolated case reports describe birth defects in babies whose mothers took pyridoxine supplements in the first half of pregnancy. A later observational study of women who took an average of 132 mg a day from week 7 of pregnancy found no link.2
A different evidence base applies to the prescription combination tablet of doxylamine and pyridoxine. Its label says no increased risk for congenital malformations has been reported in epidemiologic studies in pregnant women, and cites two meta-analyses, one of 16 cohort and 11 case-control studies and one of 12 cohort and 5 case-control studies, that found no increased risk with first-trimester use. The label is for the combination, which is a medicine, and not for a B6 supplement alone.5
What did the Cochrane review of nausea treatments find?
The 2015 Cochrane review covered 41 randomized trials with 5,449 women, testing acupressure, ginger, vitamin B6 and several antinausea drugs for nausea and vomiting before 20 weeks. It found only limited evidence from trials for vitamin B6, the doxylamine and pyridoxine combination and other drugs for mild or moderate nausea, and noted there was little information on maternal and fetal adverse outcomes.4
The authors stressed that this is not the same as saying the treatments do not work, only that there is not enough strong evidence for any one of them. For safety, it means the trials add little to the picture beyond the reports above.4
Who should ask a doctor before taking vitamin B6 in pregnancy?
- Anyone who is pregnant and considering B6 for nausea, since NIH says to consult a physician first.2
- Anyone also taking a prenatal vitamin, a B complex or a multivitamin, so the total can be compared with the limit.2
- Anyone who is offered the doxylamine and pyridoxine combination, to ask what the label says about it.5
- Anyone whose vomiting is severe or lasts, since NIH describes the common form as one that goes away at 12 to 20 weeks.2
- Anyone who takes an anti-seizure medicine such as phenytoin, phenobarbital, carbamazepine or valproic acid, or levodopa, which NIH lists as interacting with B6.2
Questions people ask
Is vitamin B6 100mg safe during pregnancy?
NIH's upper limit for adults is 100 mg a day from food and supplements together, but it does not apply to B6 taken under a doctor's care, and Europe's 2023 limit is 12 mg a day including pregnancy. NIH says to consult a physician before taking a B6 supplement in pregnancy.2,3
Is vitamin B6 safe during the first trimester?
NIH says ACOG recommends vitamin B6 under a doctor's care for nausea and vomiting, which usually appear in the first months. A Cochrane review found little information on harms. Ask your doctor.1,4
Is vitamin B6 with doxylamine safe during pregnancy?
The label of a prescription doxylamine and pyridoxine tablet says no increased risk for congenital malformations was reported in epidemiologic studies. Over-the-counter products with these ingredients are not addressed by these sources, so ask your doctor or pharmacist.5
Is vitamin B6 safe during early pregnancy?
Case reports describe birth defects after pyridoxine in the first half of pregnancy, while a later observational study found no link. Ask your doctor.2
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Sources
- National Institutes of Health, Office of Dietary Supplements. Vitamin B6: Fact Sheet for Consumers. Updated June 16, 2023. Opened 2026-10-07.
- National Institutes of Health, Office of Dietary Supplements. Vitamin B6: Fact Sheet for Health Professionals. Updated June 16, 2023. Opened 2026-10-07.
- EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA). Scientific opinion on the tolerable upper intake level for vitamin B6. EFSA J. 2023;21(5):e08006. Opened 2026-10-07.
- Matthews A, Haas DM, O'Mathuna DP, Dowswell T. Interventions for nausea and vomiting in early pregnancy (Cochrane systematic review and meta-analysis of 41 randomized trials). Cochrane Database Syst Rev. 2015;9:CD007575. Opened 2026-10-11.
- Doxylamine succinate and pyridoxine hydrochloride delayed-release tablets: prescribing information (Actavis Pharma). DailyMed, U.S. National Library of Medicine. Published November 17, 2025. Opened 2026-10-11.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.