If you are trying for a baby, you may have seen prenatal labels that say folic acid, folate or methylfolate. The names sound interchangeable, but the evidence for preventing neural tube defects is not interchangeable. For most people, the practical answer to folate vs folic acid in pregnancy is simple: eat folate-rich foods and take a daily supplement containing 400 micrograms of folic acid before conception and through the first 12 weeks.
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A higher dose is not a stronger everyday option. It is reserved for specific circumstances and should be selected with a clinician because national guidelines differ. This guide explains the difference, the timing that matters, how to read dietary folate equivalents, when B12 or medication issues change the plan, and why an MTHFR result does not automatically make methylfolate better.
Safety note: This article is educational and cannot determine your personal dose or diagnose a deficiency. Pregnancy, a previous affected pregnancy, diabetes, epilepsy, blood disorders and medicines that alter folate all deserve individual review.
For broader nutrient context, see the evidence-based vitamins and minerals guide for women in Saudi Arabia.
Key takeaways
- Folate is the umbrella term for vitamin B9 forms. Folic acid is the stable form used in many supplements and fortified foods.
The short answer: which form should you take?
For neural tube defect prevention, choose a supplement that states “folic acid” on the label. Most people who may become pregnant need 400 micrograms daily, started before conception and continued through the first 12 weeks. Food folate remains valuable, but it does not replace the proven supplement strategy.
These are compatible recommendations, not a reason to chase the largest number. In Saudi Arabia, 400 micrograms is the verified local routine recommendation. A prenatal product may contain 800 micrograms and still sit within the USPSTF range. Check the amount across every product you use so a prenatal, multivitamin and separate folic-acid tablet are not unknowingly stacked.
If you are already pregnant and did not start beforehand, begin the routine supplement promptly and tell your antenatal clinician. Missing the ideal start does not mean a neural tube defect has occurred, and taking extra tablets cannot turn back time. The useful next step is ordinary antenatal care, not panic dosing.
Why timing matters before pregnancy
Folic acid is taken before pregnancy because the biological deadline arrives early. The neural tube becomes the developing brain and spinal cord. Its closure is usually complete 26 to 28 days after fertilisation, according to the USPSTF. Many people have not yet had a positive pregnancy test by then.
This explains three parts of the advice:
- Start before conception. At least one month beforehand is the USPSTF minimum. NICE encourages folic acid before pregnancy and through the first 12 weeks.
- Take it every day. The recommendation is a daily supplement, not a large weekly amount.
- Continue through early pregnancy. The first trimester covers the period central to neural tube defect prevention.
Neural tube defects include spina bifida, which affects the spine, and anencephaly, which affects development of the brain and skull. Folic acid lowers risk, but it cannot prevent every case. Genetics, medicines, maternal conditions and other factors may contribute. Taking the recommended dose is a meaningful preventive step, not a guarantee.
For anyone who could become pregnant unexpectedly, the CDC recommends 400 micrograms daily even when pregnancy is not actively planned. That public-health approach avoids waiting for a test result after the main preventive window has begun.
Dose by situation and guideline
The numbers below report named guidance. They are not a menu for choosing your own high dose. High-dose recommendations vary by jurisdiction and depend on details such as the exact medicine, condition, family history and previous pregnancy outcome.
| Situation | Named guidance | Reported folic acid amount and timing | What you should do |
|---|---|---|---|
| Most people who may become pregnant | Saudi Ministry of Health | 400 micrograms daily before and during pregnancy until week 12 | Check that one daily supplement provides the dose and avoid duplicate products. |
| Planning pregnancy or capable of pregnancy at usual risk | USPSTF 2023 | 400 to 800 micrograms daily, starting at least 1 month before conception and continuing through the first 2 to 3 months | A product in this range meets this US recommendation. Local prescribing still governs your care. |
| Previous pregnancy affected by a neural tube defect | CDC | 4,000 micrograms daily from 1 month before the next conception through the first 3 months, after talking with a doctor | Arrange preconception review. Do not assemble this dose from multiple prenatal products. |
| Epilepsy, diabetes or a previous child with a neural tube defect | Saudi Ministry of Health | Some women are advised 5 mg | Seek preconception or early-pregnancy review. Do not change antiseizure or diabetes medicine yourself. |
Who may need a higher prescribed dose?
Most people should not self-select a 5 mg dose. The Saudi Ministry of Health identifies epilepsy, diabetes, and a previous child affected by a neural tube defect as situations in which a clinician may advise 5 mg through week 12 (Saudi Ministry of Health). CDC recommends 4,000 micrograms daily from one month before conception through the first three months after a previous neural-tube-defect-affected pregnancy (CDC). Different authorities use different high-dose regimens, so a qualified clinician should confirm the indication and prescription.
Body weight or concern about pre-eclampsia should not prompt self-directed high-dose folic acid. Ask the antenatal clinician to apply the current guidance used in your care setting.
Who may need a higher prescribed dose?
Most people should not self-select a 5 mg dose. The Saudi Ministry of Health identifies epilepsy, diabetes, and a previous child affected by a neural tube defect as situations in which a clinician may advise 5 mg through week 12 (Saudi Ministry of Health). CDC recommends 4,000 micrograms daily from one month before conception through the first three months after a previous neural-tube-defect-affected pregnancy (CDC). Different authorities use different high-dose regimens, so a qualified clinician should confirm the indication and prescription.
Body weight or concern about pre-eclampsia should not prompt self-directed high-dose folic acid. Ask the antenatal clinician to apply the current guidance used in your care setting.
Who may need a higher prescribed dose?
Most people should not self-select a 5 mg dose. The Saudi Ministry of Health identifies epilepsy, diabetes, and a previous child affected by a neural tube defect as situations in which a clinician may advise 5 mg through week 12 (Saudi Ministry of Health). CDC recommends 4,000 micrograms daily from one month before conception through the first three months after a previous neural-tube-defect-affected pregnancy (CDC). Different authorities use different high-dose regimens, so a qualified clinician should confirm the indication and prescription.
Body weight or concern about pre-eclampsia should not prompt self-directed high-dose folic acid. Ask the antenatal clinician to apply the current guidance used in your care setting.
A practical decision framework
Use this sequence rather than starting with brand claims or a genetic test.
Step 1: Could pregnancy occur?
If yes, check whether your daily supplement contains 400 micrograms of folic acid. Start now if pregnancy is planned, ideally before you stop contraception. If you use a prenatal, read the “amount per serving” and the serving size.
Step 2: Are you already pregnant?
If you are within the first 12 weeks, start or continue the routine folic-acid dose promptly. Contact your antenatal clinician early if you have any higher-risk criterion or take prescription medicine. If you are beyond 12 weeks, do not assume that folate no longer matters nutritionally, but recognise that the specific neural-tube prevention window is early.
Step 3: Does any named higher-risk factor apply?
Flag a previous neural-tube-defect-affected pregnancy, a personal or partner history, a relevant family history, type 1 or type 2 diabetes, epilepsy or anti-epileptic medicine, sickle cell anaemia, thalassaemia, certain HIV medicines, malabsorption or bariatric surgery. The exact qualifying list and dose differ by guideline. Arrange a medication and preconception review rather than buying a 5 mg product on your own.
Step 4: Could vitamin B12 deficiency be present?
Tell the clinician about a vegan or very low animal-food diet, gastric or bariatric surgery, coeliac disease, metformin, long-term acid-suppressing medicine, nitrous oxide exposure, tingling, numbness, balance problems or cognitive change. Folate and B12 deficiency can both cause enlarged red blood cells, but folic acid does not treat B12-related nerve injury (NICE NG239).
Step 5: Check the label, not the front-of-pack promise
Look for the ingredient form and amount per daily serving. “Prenatal”, “activated”, “natural” and “MTHFR-friendly” are marketing terms, not proof of neural tube defect prevention. If the label gives only micrograms DFE, inspect the ingredient panel to confirm how much folic acid is actually present.
Step 6: Recheck the plan when circumstances change
A new medicine, a confirmed deficiency, vomiting that prevents tablets staying down, bariatric surgery, a multiple-medication regimen or a new pregnancy can change the assessment. Do not stop an essential prescription medicine because it interacts with folate. The prescriber should balance both needs.
Folate, folic acid and methylfolate explained
Folate is vitamin B9 as a family of related compounds. Folic acid is a synthetic, stable member of that family used in supplements and fortified foods. 5-methyltetrahydrofolate, usually shortened to 5-MTHF or methylfolate, is another folate form sold in supplements.
The names do not create a simple natural-versus-bad-synthetic hierarchy. Naturally occurring food folate is valuable, but it is less bioavailable than folic acid. Folic acid has the clearest pregnancy-prevention evidence. The CDC states that folic acid is the only type of folate shown in studies to help prevent neural tube defects.
Your body uses folate for DNA synthesis, cell division and one-carbon metabolism. Those functions matter in rapidly dividing tissues, including bone marrow and the early embryo. Deficiency can disrupt normal red-cell formation and cause megaloblastic anaemia. During the periconception period, adequate folate supports the embryo at a stage when the neural tube is closing.
Methylfolate can raise folate status, and it is available in many prenatal products. But a plausible metabolic pathway or a higher-priced label is not the same as pregnancy-outcome evidence. Conversion factors for supplemental 5-MTHF have not been formally established in the same way as folic acid, according to the NIH Office of Dietary Supplements folate fact sheet. A product containing methylfolate is therefore not automatically superior, and it should not be assumed to replace the evidence-based folic-acid amount.
Food folate and dietary folate equivalents (DFE)
Dietary folate equivalents account for different absorption from food and folic acid. The NIH Office of Dietary Supplements defines the conversions this way:
| Source | Equivalent |
|---|---|
| Naturally occurring food folate | 1 microgram DFE = 1 microgram food folate |
| Folic acid from fortified food or a supplement taken with food | 1 microgram DFE = 0.6 micrograms folic acid |
| Folic acid supplement taken on an empty stomach | 1 microgram DFE = 0.5 micrograms folic acid |
Turned around, 400 micrograms of folic acid taken with food equals about 667 micrograms DFE. A label may therefore show both “folate, 667 mcg DFE” and “400 mcg folic acid”. That is not two separate doses. It is one amount expressed in two systems.
For women aged 19 and older, the US dietary reference is 400 micrograms DFE per day. It rises to 600 micrograms DFE in pregnancy and is 500 micrograms DFE during lactation (NIH ODS). These total-intake reference values should not be confused with the separate public-health instruction to take 400 micrograms of folic acid to prevent neural tube defects.
Folate-rich foods include:
- dark green vegetables such as spinach and other leafy greens;
- lentils, chickpeas, beans and peas;
- asparagus, Brussels sprouts and broccoli;
- oranges and some other fruits;
- avocado;
- eggs, seafood, meat and poultry; and
- fortified grain foods or cereals where the local product label confirms folic acid.
Food supports a varied diet, fibre intake and other nutrients. Still, food folate content varies, preparation can reduce it, and most prevention guidelines do not ask you to calculate meals until they equal the supplement dose. The USPSTF notes that fortified foods alone may not provide enough folic acid for optimal neural tube defect prevention. Use food and the recommended supplement together.
Do not assume a food is fortified because a similar product is fortified in another country. The evidence map did not confirm a publishable Saudi flour-fortification level from the available SFDA page. In Riyadh or elsewhere in Saudi Arabia, the product nutrition label is the safer source for what that specific food contains.
What happens after the first trimester?
The high-priority prevention window is before conception through week 12. After that point, pregnancy still raises the overall folate requirement to 600 micrograms DFE per day, but the reason and dosing conversation change. Folate continues to support cell division and red blood cell production; it is no longer sensible to describe every later-pregnancy dose as neural tube defect prevention.
Many prenatal vitamins are continued throughout pregnancy because they contain several nutrients. Do not stop or double a prenatal solely because you reached week 12. Check its folic-acid content, your diet, other supplements and any clinician-directed high-dose course. A prescriber may discontinue a separate high-dose tablet while continuing an ordinary prenatal, but that decision belongs to the care plan.
During breastfeeding, the US dietary reference is 500 micrograms DFE daily (NIH ODS). This is a nutrient requirement, not an automatic instruction to take a separate high-dose folic-acid tablet.
Folate deficiency and testing
Folate deficiency can cause megaloblastic anaemia, in which red blood cells are abnormally large and do not function normally. Possible features include fatigue, weakness, pallor, breathlessness, palpitations, a sore smooth tongue or mouth ulcers. These symptoms are nonspecific. Iron deficiency, B12 deficiency, thyroid disease, bleeding and other conditions can look similar.
Risk rises with low intake, alcohol use disorder, malabsorptive conditions such as coeliac disease or inflammatory bowel disease, and some gastric surgery. Certain medicines can interfere with absorption or metabolism. Pregnancy also increases requirements (NIH ODS).
Testing is not a single-number shortcut. Serum folate reflects recent intake; the NIH fact sheet reports that more than 3 ng/mL indicates adequacy. Red blood cell folate reflects longer-term status, with more than 140 ng/mL listed as adequate. Homocysteine can rise with poor folate status but is not specific, because B12 status, kidney function and other factors affect it too (NIH ODS). Laboratories and clinical contexts differ, so results should be interpreted with the blood count, B12 assessment, symptoms and history.
Do not use a folate result to decide whether neural tube defect prevention is necessary. Routine supplementation is timed to pregnancy possibility, not only to a documented deficiency. Conversely, if anaemia is suspected, taking folic acid without assessment can obscure an important B12 problem.
Why vitamin B12 matters before treating anaemia with folic acid
Large amounts of folate can improve the megaloblastic anaemia caused by vitamin B12 deficiency, but they do not treat B12-related neurological damage. A better blood count can therefore create false reassurance while numbness, balance trouble or other nerve problems continue.
The NIH Office of Dietary Supplements describes the historical concern as masking B12 deficiency until neurological consequences became irreversible. Current concern also includes the possibility that excess folate may exacerbate anaemia or cognitive symptoms in B12 deficiency. This is why “just try folic acid” is not a safe response to unexplained macrocytosis or anaemia.
Ask about B12 assessment if you have tingling, numbness, loss of balance, gait change, visual symptoms, cognitive difficulty or a diet or medical history that raises B12 risk. NICE NG239 says B12 deficiency should not be ruled out simply because anaemia or enlarged red blood cells are absent. Neurological symptoms can occur without either.
The warning does not mean people using the routine pregnancy-prevention dose should avoid folic acid. It means symptoms and anaemia deserve proper evaluation, and prolonged high-dose folic acid should not be self-prescribed.
The clinic's separate vitamin B12 deficiency guide explains the symptoms, risk factors and tests in more detail. If fatigue or anaemia is the main concern, the iron deficiency guide for women covers a different common cause and why laboratory assessment matters.
Medicines that can change your folic acid plan
Bring a complete medicine and supplement list to preconception or early-pregnancy care. Include nonprescription products and exact doses.
Anti-epileptic medicines
Phenytoin, carbamazepine and valproate can lower folate status, while folate supplementation can affect levels of some anti-epileptic medicines. Some are also independently associated with fetal risk. Do not stop, switch or reduce an anti-epileptic medicine abruptly. Preconception review should coordinate seizure control, medicine choice and folic-acid dosing (NIH ODS).
Methotrexate
Methotrexate antagonises folate. Folic or folinic acid may be used alongside low-dose methotrexate for rheumatoid arthritis or psoriasis to reduce adverse effects, but oncology regimens have different aims and require the oncology team's direction. Methotrexate also raises major pregnancy-planning issues. Do not add folate, stop methotrexate or try to conceive without prescriber advice (NIH ODS).
Sulfasalazine
Sulfasalazine can inhibit intestinal folate absorption. People using it for inflammatory bowel disease or inflammatory arthritis may need an individual plan that accounts for the condition, pregnancy and other medicines (NIH ODS).
HIV medicines and other interacting drugs
NICE includes certain HIV medicines among drugs that can alter folic-acid absorption or metabolism. The exact drug matters. Do not infer that every medicine in a broad category requires 5 mg. A pharmacist, obstetric clinician or prescribing specialist should check the current regimen.
MTHFR, methylfolate and what the evidence does not show
MTHFR is an enzyme involved in folate metabolism. The common C677T variant can reduce enzyme activity, but carrying a variant is not the same as having folate deficiency, recurrent pregnancy loss or a need for a special prenatal product.
The central practical point is clear: the CDC recommends 400 micrograms of folic acid daily for people who could become pregnant, including those with an MTHFR variant. The NIH Office of Dietary Supplements says 400 micrograms of folic acid increases blood folate regardless of MTHFR genotype and helps prevent neural tube defects even with the variant. Evidence that MTHFR carriers obtain better pregnancy outcomes from methylfolate is inconclusive.
Routine MTHFR testing is not supported as a way to choose a prenatal vitamin. The American College of Medical Genetics and Genomics practice guideline concluded that MTHFR polymorphism testing has minimal clinical utility and should not be part of routine thrombophilia evaluation. It also states that people homozygous for the common variant who have normal homocysteine can be reassured that their MTHFR status has not been shown to raise venous-thromboembolism or recurrent-pregnancy-loss risk.
Three misleading claims deserve a direct answer:
- “I cannot process folic acid.” Common MTHFR variants may reduce enzyme activity, but they do not make folic acid unusable.
- “Methylfolate prevents more birth defects.” No authoritative source in this evidence set establishes superior neural tube defect prevention with methylfolate.
- “An MTHFR result means I need 5 mg.” High-dose criteria come from clinical history, conditions and medicines under a named guideline, not from consumer genetic testing alone.
If a specialist recommends a different folate form for a separate diagnosed condition, ask what outcome the choice targets and whether the product still supplies the evidence-based folic-acid amount for pregnancy prevention. Do not treat a supplement label as genetic counselling.
🚨 Folic acid safety, side effects and red flags
Folic acid at usual preventive doses has a strong safety record. The USPSTF found adequate evidence that usual-dose supplementation is not associated with serious harms.
For adults, the US tolerable upper intake level is 1,000 micrograms per day of synthetic folate from supplements and fortified foods. It does not include naturally occurring food folate, and it does not apply to high-dose treatment under medical supervision (NIH ODS). The distinction matters: a clinician-directed 4,000- or 5,000-microgram regimen can be appropriate for a defined high-risk situation even though it exceeds the general upper limit. That is not permission to take it “just in case”.
Check for duplicate folic acid in a prenatal, multivitamin, B-complex, fortified nutrition powder and separate tablet. More is not proven to prevent more defects in standard-risk pregnancy. The NIH review notes unresolved concerns at high intakes, including detectable unmetabolised folic acid and observational developmental findings, but these data do not show that ordinary recommended folic acid is dangerous.
Seek urgent medical care now if
- you are pregnant and have heavy bleeding, severe abdominal or pelvic pain, fainting, chest pain, severe breathlessness or feel acutely very unwell;
- you develop signs of a serious allergic reaction after a supplement, such as facial or throat swelling, difficulty breathing or collapse; or
- you have rapidly worsening weakness, difficulty walking, loss of balance, new confusion or major visual change.
Arrange prompt clinical assessment if
- tingling, numbness, balance trouble, gait change or cognitive symptoms suggest possible B12-related nerve involvement;
- fatigue, pallor, breathlessness, palpitations, a sore tongue or mouth ulcers persist;
- vomiting prevents you from keeping a prenatal supplement down;
- you discover pregnancy while taking methotrexate, valproate, carbamazepine, phenytoin or another medicine that may affect pregnancy or folate; or
- you have a previous affected pregnancy, diabetes, epilepsy, sickle cell anaemia, thalassaemia, bariatric surgery or significant malabsorption and do not yet have a dose plan.
Do not wait for a routine supplement appointment if severe symptoms are present. A vitamin article cannot assess pregnancy emergencies, medication toxicity, severe anaemia or neurological injury.
Common myths, corrected
Myth: Food folate and folic acid are exactly the same.
Fact: They belong to the same vitamin family, but their bioavailability and evidence base differ. DFE helps compare absorption.
Myth: “Natural folate” is always safer or better.
Fact: Folate-rich food is healthy, while folic acid is the only form shown to prevent neural tube defects in intervention studies cited by CDC.
Myth: Everyone should take 5 mg to be safe.
Fact: High-dose folic acid is a clinician-directed strategy for specified risk. It exceeds the adult general upper limit and is not a routine upgrade.
Myth: BMI above 25 automatically means 5 mg.
Fact: NICE 2025 says BMI of 25 kg/m² or more alone does not require more than 400 micrograms.
Myth: An MTHFR variant means folic acid will not work.
Fact: CDC recommends folic acid regardless of common MTHFR genotype, and routine MTHFR testing is not recommended for this decision.
Myth: A normal blood count rules out B12 deficiency.
Fact: Neurological B12 deficiency can occur without anaemia or macrocytosis, according to NICE NG239.
Myth: Food folate and folic acid are exactly the same.
Fact: They belong to the same vitamin family, but their bioavailability and evidence base differ. DFE helps compare absorption.
Myth: “Natural folate” is always safer or better.
Fact: Folate-rich food is healthy, while folic acid is the only form shown to prevent neural tube defects in intervention studies cited by CDC.
Myth: Everyone should take 5 mg to be safe.
Fact: High-dose folic acid is a clinician-directed strategy for specified risk. It exceeds the adult general upper limit and is not a routine upgrade.
Myth: BMI above 25 automatically means 5 mg.
Fact: NICE 2025 says BMI of 25 kg/m² or more alone does not require more than 400 micrograms.
Myth: An MTHFR variant means folic acid will not work.
Fact: CDC recommends folic acid regardless of common MTHFR genotype, and routine MTHFR testing is not recommended for this decision.
Myth: A normal blood count rules out B12 deficiency.
Fact: Neurological B12 deficiency can occur without anaemia or macrocytosis, according to NICE NG239.
Frequently asked questions
1. How much folic acid should I take before pregnancy?
For most people in Saudi guidance, take 400 micrograms daily before conception and through week 12. USPSTF gives a routine range of 400 to 800 micrograms, so check the label and avoid stacking multiple products.
2. How long before trying should I start folic acid?
Start at least one month before conception. Because the neural tube closes about 26 to 28 days after fertilisation, taking folic acid only after a positive test may miss part of the preventive window.
3. I am six weeks pregnant and did not take folic acid. What now?
Start the routine folic-acid supplement promptly and contact your antenatal clinician, especially if a high-risk factor or interacting medicine applies. Do not take several tablets to “catch up”; extra dosing cannot replace earlier exposure.
4. Is folate from food enough in pregnancy?
Food folate is beneficial, but major prevention guidelines still advise a folic-acid supplement. Food content and absorption vary, and fortified foods alone may not deliver the studied preventive amount consistently.
5. Is methylfolate better than folic acid for MTHFR?
No pregnancy-prevention superiority has been established. CDC recommends 400 micrograms of folic acid even for people with common MTHFR variants, and folic acid remains the form directly shown to prevent neural tube defects.
6. Who needs 5 mg folic acid?
Only someone whose clinician identifies a qualifying high-risk situation under the guideline used for their care. NICE examples include relevant personal, partner or family history, a previous affected pregnancy, type 1 or type 2 diabetes, certain haematological conditions, and medicines that alter folate; Saudi MOH specifically names epilepsy, diabetes and a previous child with a neural tube defect.
7. Can folic acid hide vitamin B12 deficiency?
Large amounts can improve the blood-count abnormality without treating B12-related nerve damage. If you have tingling, numbness, balance problems, cognitive change or a B12 risk factor, ask for clinical assessment rather than treating suspected anaemia with folic acid alone.
8. Can I keep taking folic acid after 12 weeks?
Many people continue a prenatal supplement throughout pregnancy, and the pregnancy folate requirement remains 600 micrograms DFE per day. The need for a separate folic-acid tablet, especially a high-dose one, should be reviewed rather than continued automatically.
The bottom line
For most people, the evidence-based choice is not complicated: eat folate-rich foods and take a daily supplement containing 400 micrograms of folic acid before conception and through the first 12 weeks. Start early. Check the label. Do not rely on food alone for neural tube defect prevention, and do not swap to methylfolate because a marketing page or consumer genetic result says folic acid is inferior.
The exceptions need precision. A previous affected pregnancy, diabetes, epilepsy or relevant medicines, blood disorders, family history and malabsorption can change the plan. Named guidelines differ between 4,000 and 5,000 micrograms in specific higher-risk situations, which is exactly why the high dose should come from a clinician rather than a shelf decision.
If you are planning pregnancy or have just had a positive test, bring your prenatal label, medicine list and relevant family or pregnancy history to a qualified clinician. If you are also weighing claims about vitamin D and conception, read the clinic's separate vitamin D and fertility evidence guide. Use your established obstetric, primary-care or specialist pathway, and seek urgent care for red-flag symptoms.
References
- Saudi Ministry of Health. Pregnancy Planning. https://www.moh.gov.sa/en/healthawareness/educationalcontent/wh/pages/008.aspx
- US Preventive Services Task Force. Folic Acid Supplementation to Prevent Neural Tube Defects: Preventive Medication. 2023. https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/folic-acid-for-the-prevention-of-neural-tube-defects-preventive-medication
- Centers for Disease Control and Prevention. About Folic Acid. https://www.cdc.gov/folic-acid/about/index.html
- NIH Office of Dietary Supplements. Folate: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/
- National Institute for Health and Care Excellence. Vitamin B12 deficiency in over 16s: diagnosis and management. NG239 Recommendations. 2024. https://www.nice.org.uk/guidance/ng239/chapter/Recommendations
- Hickey SE, Curry CJ, Toriello HV. ACMG Practice Guideline: lack of evidence for MTHFR polymorphism testing. Genetics in Medicine. 2013;15:153-156. https://www.nature.com/articles/gim2012165