Does vitamin B6 help with pregnancy nausea?

Probably a little, for mild nausea, and nobody has measured it well. A 2026 network meta-analysis of 24 randomized trials in 3017 pregnant women placed vitamin B6 among the treatments that might reduce nausea and vomiting, with certainty rated low to moderate. The treatments in those trials lasted 3 to 7 days. The 2015 Cochrane review of 41 trials in 5449 women could not pool the vitamin B6 trials at all, because they were too different from each other.

Unsettled. Every review points the same way and none is confident. The 2016 JAMA review of 78 studies with 8930 participants found pyridoxine better than placebo for mild symptoms only, and rated the overall quality low. The 2018 network meta-analysis of 42 trials rated the evidence for everything except ginger as very low. The Cochrane authors add a fair warning of their own. A lack of high-quality evidence is not the same thing as a treatment that fails.

What the trials found

Vitamin B6 on its own

A 2023 pooled analysis of 18 studies looked at pyridoxine given alone or with another active ingredient. It improved nausea by 0.78 on the Rhodes score (95% CI 0.26 to 1.31) and by 0.75 on the PUQE score (95% CI 0.28 to 1.22). Heterogeneity was moderate on one of the two scales.

One triple-blind trial shows the kind of dose behind these results. In 77 women at 6 to 16 weeks of pregnancy, 40 mg of vitamin B6 twice a day for 4 days lowered the Rhodes score more than placebo. The abstract gives only a P value and no effect size. That is 80 mg a day, well above the European upper limit described further down.

Ginger is the usual alternative. A meta-analysis of 13 trials with 1174 women found no significant difference between ginger and vitamin B6 for overall symptoms, with an odds ratio of 1.239 (95% CI 0.495 to 3.102). The review reports odds and no absolute rates. Being level with ginger also does not show that either one beats placebo.

Severe sickness, where B6 did not help

Hyperemesis gravidarum is the form that puts women in hospital. In the one trial of vitamin B6 for it, 92 participants within a Cochrane review, women on B6 stayed in hospital 0.80 days longer than on placebo (95% CI 0.08 to 1.52), on moderate-quality evidence. A single small trial makes the direction more useful than the exact size.

B6 with doxylamine, the version usually prescribed

Most prescriptions pair pyridoxine with doxylamine, an antihistamine. In the trial that licensed the delayed-release combination, 256 women improved by 4.8 points against 3.9 on placebo over two weeks. Most of the improvement happened on placebo too, which is what nausea of pregnancy does on its own. In a newer trial of 352 women the gap was 1.0 point, and the authors call its clinical importance uncertain.

Against ondansetron, in 36 women, the combination came out clearly second. Median nausea fell 51 mm on a 100 mm scale on ondansetron and 20 mm on pyridoxine with doxylamine over 5 days. Uneven dropout, 13 of 18 against 17 of 18 completing, makes the size of that gap unreliable.

Who should be careful

Not for everyone. The dose guidelines suggest is above Europe's safe upper limit. The US Office of Dietary Supplements reports that ACOG recommends 10 to 25 mg three or four times a day, which is 30 to 100 mg a day. In 2023 EFSA set the upper limit for adults at 12 mg a day, and it covers pregnant and lactating women. The US limit is 100 mg a day and does not apply to people taking B6 as medical treatment, who the Office says should be under a physician's care.

The harm both limits guard against is nerve damage. A review of the nerve literature concluded that more than 50 mg a day for a long stretch may be harmful and should be discouraged, and its authors say the data are limited. A review of case reports on excessive vitamin B6 intake in women counted neurological symptoms such as burning, tingling or unsteadiness in 164 of 1226 people. Those are selected published cases with no comparison group, so the proportion is not a rate in ordinary users, and the reports are not limited to women taking B6 for nausea.

Inside the trials, safety was reported only as figures from single trials, not pooled. Some women on B6 reported sedation (17.5%) or heartburn (3.2%), with no placebo figure beside them, and treatment lasted days, too short for rare or late harms to show.

For the combination with doxylamine, 27 cohort and case-control studies found no rise in birth defects after first-trimester use of Bendectin, with a relative risk of any malformation of 0.95 (95% CI 0.88 to 1.04). That evidence is observational, covers the combination product rather than high-dose B6 alone, and gives no absolute rates. The newer trial of 352 women recorded more babies small for gestational age on doxylamine with pyridoxine, an odds ratio of 3.8 (95% CI 1.0 to 14.1). It was a secondary outcome, the interval touches 1.0 and the abstract gives no absolute numbers. It is a signal to watch and not a demonstrated harm.

What expert bodies say

The professional bodies treat B6 as a first step, mostly together with doxylamine. ACOG, as reported by the US Office of Dietary Supplements, recommends B6 on its own first and adding doxylamine if there is no improvement. The 2024 RCOG Green-top guideline in the UK names doxylamine with pyridoxine among first-line antiemetics with a grade A recommendation, and it recommends the combination drug, not B6 alone. The 2024 AGA practice update starts stepwise treatment with vitamin B6 and doxylamine, on expert opinion without a systematic review, as the AGA itself states.

Where the agencies part ways is the dose. If nausea is mild, B6 is a fair thing to raise with whoever looks after your pregnancy, and the dose is theirs to set. Hyperemesis, the severe form that can put women in hospital, is different: B6 did not help it in the one trial that tested it.

How we searched

What would change this answer

• A placebo-controlled trial that tests vitamin B6 alone at several doses, including doses at or below the European limit of 12 mg a day. No such dose-finding trial turned up, and the trial dose quoted above is several times that limit.
• Trials longer than a week. The network meta-analysis could not run a one-month analysis, because the treatments it pooled lasted 3 to 7 days.
• Safety data that can be pooled, with placebo rates beside the B6 rates. Today the harms evidence is a handful of single-trial percentages and case reports.
• A registered trial now under way. Our snapshot of ClinicalTrials.gov returned none for pyridoxine or doxylamine in pregnancy.

Sources

1. ev-b6nvp-01 · Meta-analysis or systematic review · systematic review and network meta-analysis of randomized controlled trials · n = 3017
   Conclusions: This study indicates that both pharmacological (vitamin B6, metoclopramide, dimenhydrinate) and non-pharmacological (ginger, quince, acupressure, acupuncture) interventions might be effective in reducing symptoms of nausea and vomiting in pregnancy.
   
   Who: Pregnant women with nausea and vomiting in the first and early second trimester, 24 placebo-controlled RCTs
   Effect: most interventions, vitamin B6 included, reduced symptom scores vs placebo at 1 week; network I2 68.6%; CINeMA certainty low to moderate
   Certainty: Ranking rests mostly on indirect comparisons; 14 of 24 trials from Iran; treatments lasted 3 to 7 days. No 1-month analysis was possible.
   Nutrients, 2026 · checked 2026-10-06 · we read the abstract
2. ev-b6nvp-02 · Randomized controlled trial(s) · systematic review and network meta-analysis of randomized controlled trials, safety outcomes narrative · n = —
   Certain patients receiving B6 supplements experienced heartburn (3.2%), sedation (17.5%), headache (3.1%) [32], or i drowsiness (4.46%) [31].
   
   Who: Pregnant women in the vitamin B6 arms of the included trials
   Effect: B6 arms: sedation 17.5%, heartburn 3.2%, headache 3.1% in one trial, drowsiness 4.46% in another; no safety meta-analysis
   Certainty: Single-trial percentages without placebo comparison; short treatment, so rare or late harms would not show.
   Nutrients, 2026 · checked 2026-10-06 · we read the fulltext
3. ev-b6nvp-03 · Meta-analysis or systematic review · network meta-analysis and trial sequential analysis of randomized clinical trials · n = 42 trials
   Of these interventions, ginger and vitamin B6 were also associated with better vomiting control and less incidence of adverse events.
   
   Who: Pregnant women with nausea and vomiting, 50 RCTs reviewed, 42 meta-analyzed
   Effect: vitamin B6 associated with reduced nausea scores, better vomiting control and fewer adverse events vs placebo; strength of evidence very low
   Certainty: Effect sizes are not in the abstract; the authors themselves ask for extreme caution.
   Expert Rev Clin Pharmacol, 2018 · checked 2026-10-06 · we read the abstract
4. ev-b6nvp-04 · Meta-analysis or systematic review · systematic review of randomized and nonrandomised studies, narrative synthesis · n = 8930
   Conclusions and Relevance: For mild symptoms of nausea and emesis of pregnancy, ginger, pyridoxine, antihistamines, and metoclopramide were associated with greater benefit than placebo.
   
   Who: Pregnant women with nausea and vomiting or hyperemesis gravidarum, 67 RCTs and 11 nonrandomised studies
   Effect: pyridoxine associated with greater benefit than placebo for mild symptoms; pyridoxine-doxylamine for moderate symptoms; quality low; no meta-analysis
   Certainty: Narrative synthesis because of heterogeneity; the benefit for B6 alone is limited to mild symptoms.
   JAMA, 2016 · checked 2026-10-06 · we read the abstract
5. ev-b6nvp-05 · Meta-analysis or systematic review · Cochrane systematic review of randomized controlled trials · n = 5449
   There was only limited evidence from trials to support the use of pharmacological agents including vitamin B6, Doxylamine-pyridoxoine and other anti-emetic drugs to relieve mild or moderate nausea and vomiting.
   
   Who: Women up to 20 weeks of pregnancy with nausea, vomiting or retching, hyperemesis excluded
   Effect: no pooled estimate for vitamin B6; limited evidence for mild or moderate symptoms
   Certainty: The authors stress that a lack of high-quality evidence is not the same as ineffectiveness.
   Cochrane Database Syst Rev, 2015 · checked 2026-10-06 · we read the abstract
6. ev-b6nvp-06 · Meta-analysis or systematic review · meta-analysis of randomized controlled trials · n = 1174
   Besides, ginger intervention has no significant effect on improving general symptom of NVP [OR = 1.239, 95% CI = (0.495, 3.102), I2 = 57.3%], relieving severity of nausea [SMD = 0.199, 95% CI = (-0.102, 0.500), I2 = 65.7%], reducing vomiting [SMD = 0.331, 95% CI = (-0.145, 0.808), I2 = 85.9%], compared with vitamin B6.
   
   Who: Pregnant women with nausea and vomiting, RCTs of ginger vs placebo or vitamin B6
   Effect: ginger vs vitamin B6: general symptoms OR 1.239 (95% CI 0.495 to 3.102); nausea SMD 0.199 (95% CI -0.102 to 0.500); vomiting SMD 0.331 (95% CI -0.145 to 0.808)
   Certainty: High heterogeneity for vomiting (I2 85.9%). Equal to ginger is not proof that either beats placebo; OR is odds, not risk.
   J Matern Fetal Neonatal Med, 2022 · checked 2026-10-06 · we read the abstract
7. ev-b6nvp-07 · Randomized controlled trial(s) · triple-blind three-arm randomized placebo-controlled trial, 4 days · n = 77
   In these women ginger, 500 mg twice daily, vitamin B6 40 mg twice daily and placebo twice daily were administered for 4 d.
   
   Who: Pregnant women with mild to moderate nausea and vomiting at 6 to 16 weeks; 28 ginger, 26 B6, 23 placebo
   Effect: B6 more effective than placebo on total Rhodes score (p = .007); ginger vs B6 no significant difference (p = .128)
   Certainty: Only P values in the abstract, no effect size; 80 mg/day is well above the EFSA UL of 12 mg/day.
   J Matern Fetal Neonatal Med, 2018 · checked 2026-10-06 · we read the abstract
8. ev-b6nvp-08 · Position of an expert body · agency fact sheet summarizing a professional guideline · n = —
   The American College of Obstetrics and Gynecology (ACOG) recommends monotherapy with 10–25 mg of vitamin B6 three or four times a day to treat nausea and vomiting in pregnancy [29].
   
   Who: Pregnant women with nausea and vomiting
   Effect: ACOG monotherapy 10 to 25 mg three or four times daily (30 to 100 mg/day); add doxylamine if no improvement
   Certainty: Secondary report of the ACOG Practice Bulletin; ACOG full text not opened (paywall).
   NIH Office of Dietary Supplements, Vitamin B6 Fact Sheet for Health Professionals · checked 2026-10-06 · we read the section
9. ev-b6nvp-09 · Position of an expert body · agency fact sheet citing the Food and Nutrition Board · n = —
   The ULs do not apply to individuals receiving vitamin B6 for medical treatment, but such individuals should be under the care of a physician.
   
   Who: Adults, including people treated with vitamin B6
   Effect: US UL 100 mg/day for adults; lower for children and adolescents
   Certainty: Set from long-term use data; the FNB halved a 200 mg/day no-neuropathy dose.
   NIH Office of Dietary Supplements, Vitamin B6 Fact Sheet for Health Professionals · checked 2026-10-06 · we read the section
10. ev-b6nvp-10 · Position of an expert body · scientific opinion based on systematic reviews · n = —
    From the midpoint of the range of these two ULs and rounding down, a UL of 12 mg/day is established by the Panel for vitamin B6 for adults (including pregnant and lactating women).
    
    Who: Adults including pregnant and lactating women
    Effect: EU UL 12 mg/day (reference point 50 mg/day from a case-control study, uncertainty factor 4), vs US UL 100 mg/day
    Certainty: Bodies diverge: EFSA treats neuropathy risk as starting far lower than the FNB. Critical effect is peripheral neuropathy.
    EFSA NDA Panel, EFSA Journal, 2023 · checked 2026-10-06 · we read the abstract
11. ev-b6nvp-11 · Observational data · meta-analysis of observational studies · n = 27 studies
    The pooled estimate of the relative risk of any malformation at birth in association with exposure to Bendectin in the first trimester was 0.95 (95% Cl 0.88 to 1.04).
    
    Who: Infants of mothers exposed to Bendectin in the first trimester, 16 cohort and 11 case-control studies
    Effect: any malformation RR 0.95 (95% CI 0.88 to 1.04); defect-specific RRs 0.81 to 1.11, all CIs including 1
    Certainty: Observational data on the combination product, not on pyridoxine alone or on high-dose B6.
    Teratology, 1994 · checked 2026-10-06 · we read the abstract
12. ev-b6nvp-12 · Position of an expert body · national clinical guideline · n = —
    There are safety and efficacy data for first line antiemetics such as anti (H1) histamines, phenothiazines and doxylamine/pyridoxine (Xonvea®) and they should be prescribed initially when required for NVP and HG (Appendix III).
    
    Who: Women with nausea and vomiting of pregnancy or hyperemesis gravidarum in the UK
    Effect: doxylamine/pyridoxine first line (Grade A); pyridoxine alone not listed in the abstract
    Certainty: Abstract only; the guideline recommends the combination drug, not vitamin B6 on its own.
    BJOG, 2024 · checked 2026-10-06 · we read the abstract
13. ev-b6nvp-13 · Position of an expert body · expert review, best practice advice · n = —
    In addition to standard diet and lifestyle measures, stepwise treatment consists of symptom control with vitamin B6 and doxylamine, hydration, and adequate nutrition; ondansetron, metoclopramide, promethazine, and intravenous glucocorticoids may be required in moderate to severe cases.
    
    Who: Pregnant patients with nausea and vomiting
    Effect: stepwise treatment starts with vitamin B6 and doxylamine; early treatment may reduce progression to hyperemesis
    Certainty: Expert opinion without systematic review, as the AGA states.
    Gastroenterology, 2024 · checked 2026-10-06 · we read the abstract
14. b6-t1 · Meta-analysis or systematic review · systematic review and meta-analysis · n = 18 studies
    Supplementation of pyridoxine alone as well as combined treatment of pyridoxine with an active ingredient as the intervention significantly improved the symptoms of nausea according to Rhode's score [0.78 [95% CI: 0.26, 1.31; p = 0.003; I2 = 57%, p = 0.10)] and PUQE score [0.75 (95% CI: 0.28, 1.22; p = 0.002; I2 = 0%, p = 0.51)], respectively.
    
    Who: pregnant women with nausea and vomiting, 18 studies
    Effect: Rhode's score 0.78 (95% CI 0.26 to 1.31), PUQE score 0.75 (95% CI 0.28 to 1.22)
    Certainty: moderate heterogeneity on one of the two scales
    Jayawardena et al., Archives of Gynecology and Obstetrics, 2023 · checked 2026-09-16 · we read the abstract
15. b6-t2 · Meta-analysis or systematic review · systematic review of the literature on pyridoxine and neuropathy · n = literature review
    Supplementation with pyridoxine at doses greater than 50 mg/d for extended duration may be harmful and should be discouraged.
    
    Who: people with peripheral neuropathy attributed to vitamin B6 deficiency or excess
    Effect: doses above 50 mg a day for extended periods judged potentially harmful
    Certainty: limited data, authors say so plainly
    Ghavanini and Kimpinski, Journal of Clinical Neuromuscular Disease, 2014 · checked 2026-09-16 · we read the abstract
16. b6-t3 · Meta-analysis or systematic review · Cochrane systematic review of randomized controlled trials, one trial contributing this comparison · n = 92 participants in the vitamin B6 trial, 2,052 women across the review
    In a study with 92 participants, women taking vitamin B6 had a slightly longer hospital stay compared with placebo (mean difference (MD) 0.80 days, 95% CI 0.08 to 1.52, moderate-quality evidence). There was insufficient evidence to demonstrate a difference in other outcomes including mean number of episodes of emesis (MD 0.50, 95% CI -0.40 to 1.40, low-quality evidence) or side effects.
    
    Who: pregnant women up to 20 weeks with hyperemesis gravidarum; the review covers 25 trials, the vitamin B6 comparison rests on one of them
    Effect: length of hospital stay mean difference 0.80 days longer (95% CI 0.08 to 1.52) on vitamin B6 than on placebo; episodes of emesis mean difference 0.50 (95% CI -0.40 to 1.40), no clear difference
    Certainty: moderate-quality evidence for the hospital stay, low for the emesis count; a single small trial, so the direction matters more than the exact size
    Boelig et al., Cochrane Database of Systematic Reviews, 2016 · checked 2026-09-17 · we read the abstract
17. b6-t4 · Randomized controlled trial(s) · multicentre, randomized, double-blind, placebo-controlled 2x2 factorial trial over 14 days · n = 352 women
    Participants receiving acupuncture (mean difference [MD], -0.7 [95% CI, -1.3 to -0.1]), doxylamine-pyridoxine (MD, -1.0 [CI, -1.6 to -0.4]), and the combination of both (MD, -1.6 [CI, -2.2 to -0.9]) had a larger reduction in PUQE score over the treatment course than their respective control groups (sham acupuncture, placebo, and sham acupuncture plus placebo).
    
    Who: women in early pregnancy with moderate to severe nausea and vomiting, at 13 tertiary hospitals in mainland China
    Effect: reduction in the Pregnancy-Unique Quantification of Emesis score against control: doxylamine-pyridoxine mean difference -1.0 (95% CI -1.6 to -0.4), acupuncture -0.7 (95% CI -1.3 to -0.1), both together -1.6 (95% CI -2.2 to -0.9)
    Certainty: the trial authors themselves call the clinical importance uncertain because the magnitude is modest; pyridoxine was given with doxylamine, so this is not a test of vitamin B6 alone
    Wu et al., Annals of Internal Medicine, 2023 · checked 2026-09-17 · we read the abstract
18. b6-t5 · Randomized controlled trial(s) · secondary outcome of the same randomized, double-blind, placebo-controlled trial · n = 352 women
    Compared with placebo, a higher risk for births with children who were small for gestational age was observed with doxylamine-pyridoxine (odds ratio, 3.8 [CI, 1.0 to 14.1]).
    
    Who: the same 352 women in early pregnancy with moderate to severe nausea and vomiting, followed to delivery
    Effect: small for gestational age at birth, odds ratio 3.8 (95% CI 1.0 to 14.1) against placebo
    Certainty: a secondary outcome with a confidence interval that touches 1.0 and runs to 14: this is a signal to watch, not a demonstrated harm, and it attaches to the combination, not to vitamin B6 on its own
    Wu et al., Annals of Internal Medicine, 2023 · checked 2026-09-17 · we read the abstract
19. b6-t6 · Randomized controlled trial(s) · randomized, double-blind, multicentre, placebo-controlled trial analyzed by intention to treat · n = 256 women, 131 on doxylamine succinate 10 mg with pyridoxine hydrochloride 10 mg and 125 on placebo
    Diclectin use resulted in a significantly larger improvement in symptoms of nausea and vomiting of pregnancy compared with placebo based on both the pregnancy unique quantification of emesis score (-4.8 ± 2.7 vs -3.9 ± 2.6; P = .006) and quality of life.
    
    Who: pregnant women with nausea and vomiting of pregnancy, treated for 14 days
    Effect: change in the Pregnancy-Unique Quantification of Emesis score -4.8 (SD 2.7) against -3.9 (SD 2.6) on placebo, P = 0.006, a difference of about 0.9 points
    Certainty: most of the improvement happened in the placebo group too, which is what nausea of pregnancy does on its own; the tested product pairs pyridoxine with an antihistamine
    Koren et al., American Journal of Obstetrics and Gynecology, 2010 · checked 2026-09-17 · we read the abstract
20. b6-t7 · Randomized controlled trial(s) · double-blind randomized controlled trial over five days of treatment · n = 36 women, 18 per group, of whom 13 and 17 completed follow-up
    Patients randomized to ondansetron were more likely to have an improvement in their baseline nausea as compared with those using pyridoxine and doxylamine over the course of 5 days of treatment (median VAS score decreased 51 mm [interquartile range 37-64] compared with 20 mm [8-51]; P=.019).
    
    Who: pregnant women with nausea and vomiting of pregnancy, randomized to 4 mg ondansetron or 25 mg pyridoxine plus 12.5 mg doxylamine
    Effect: median nausea on a 100 mm visual analog scale fell 51 mm (IQR 37 to 64) on ondansetron against 20 mm (IQR 8 to 51) on pyridoxine-doxylamine, P = 0.019
    Certainty: very small trial with uneven completion, 13 of 18 against 17 of 18, so the size of the gap is unreliable even though the direction was significant
    Oliveira et al., Obstetrics and Gynecology, 2014 · checked 2026-09-17 · we read the abstract
21. b6-t8 · Observational data · systematic review of published reports of adverse effects of high-dose vitamin B6 in pregnancy · n = 1,226 individuals for neurological symptoms and 245 women for pregnancy outcomes
    Among these sources, 12 reports detailed the adverse effects of excessive vitamin B6 intake in women; 164/1226 individuals experienced neurological symptoms such as burning, tingling, paresthesia, ataxia, or perioral numbness. Additionally, out of 245 women, four experienced miscarriages and one had an intrauterine demise.
    
    Who: women with excessive vitamin B6 intake described in 12 of 19 reports found in MEDLINE by a review of high-dose B6 for nausea and vomiting of pregnancy
    Effect: 164 of 1,226 people had neurological symptoms including burning, tingling, paraesthesia, ataxia or perioral numbness; among 245 women there were four miscarriages and one intrauterine death
    Certainty: a review of case reports and series with no comparison group: the denominators come from selected published reports, so the proportion is not an incidence rate in ordinary users
    Chen et al., International Journal of Gynaecology and Obstetrics, 2025 · checked 2026-09-17 · we read the abstract