- Cost: The Chinese source mentions a bottle costing tens of yuan and a free mainland-China programme for rural women; eligibility, current prices and access remain unverified. Remembering a daily supplement requires consistency.
- In plain language: Periconceptional supplementation can reduce neural-tube defects, including anencephaly and spina bifida. The source’s general 0.4 mg daily advice must not be assumed sufficient for every person, especially after an affected pregnancy; individualized dose guidance remains to be checked.
- Benefit: The cited 2015 Cochrane review reports five trials and 6,708 births with infant-outcome information, with an overall neural-tube-defect risk ratio of 0.31 (95% CI 0.17–0.58). Recurrence analysis reports 0.34 (0.18–0.64). These are relative comparisons, not absolute probabilities. Its subgroup findings about doses and combined vitamins do not establish that all doses are clinically interchangeable.
- Evidence grade: A, assigned by the Chinese source. The review rates the overall neural-tube-defect outcome highly; that does not mean every outcome or trial has the same evidence quality.
- Source: De-Regil LM, Peña-Rosas JP, Fernández-Gaxiola AC, Rayco-Solon P (2015). Effects and safety of periconceptional oral folate supplementation for preventing birth defects. Cochrane Database of Systematic Reviews, (12), CD007950. https://doi.org/10.1002/14651858.CD007950.pub3
- Notes: The Chinese source advises starting three months before conception because neural-tube development happens early, and continuing through the first three months of pregnancy. Its precise timing and 28-day closure statement still require clinical-guideline verification. The review does not clearly establish benefits for other listed defects or miscarriage; lack of a clear effect is not proof of no effect. The source refers vegan pregnant people to chapter 20, entry 14 on vitamin B12; that entry requires its own review.
Editorial scope: Free-service eligibility applies to a Chinese programme claim, not worldwide access. The original title’s 0.4 mg is retained as a source claim pending current standard- and high-risk-dose checks. This is an unapproved translation and evidence draft; no individualized regimen or publication approval is supplied.
UK guideline scope: The NHS page reviewed in June 2026 recommends 400 micrograms (0.4 mg) daily when trying to conceive, ideally starting three months beforehand, or starting as soon as pregnancy is recognized, through 12 weeks. It advises a prescribed 5 mg dose for specified higher-risk situations, including a previous affected pregnancy. This UK guidance supports distinguishing routine and high-risk doses; it does not establish the correct regimen or programme eligibility in every country. Do not interpret missing the preconception start as a reason not to seek guidance or begin appropriate supplementation once pregnancy is recognized.
Early-development evidence: CDC’s May 2025 neural-tube-defect page describes neural-tube folding and closure in the third and fourth weeks and emphasizes development before pregnancy is often recognized. This supports early supplementation, but its wording alone does not verify the Chinese source’s exact “within 28 days after conception” clock. That precise timing statement remains pending rather than converting pregnancy-week wording silently.