Folic acid prevents most neural tube defects, but only if blood levels are adequate when the neural tube closes, about four weeks after conception, often before pregnancy is known. That timing is why all women who could conceive are advised four hundred micrograms daily, with higher prescription doses for defined risk groups. Select your situation for the matching recommendation.
Your visual report appears here
Fill in the form and press Calculate. You will get your number, an interpretation chip, and a personalized chart pack drawn instantly in your browser.
- Risk spectrum with your position marked
- Reference ranges from the original publication
- Shareable link, nothing stored
Scientific references
The neural tube, origin of the brain and spine, closes by day twenty eight of pregnancy, a moment most women have not yet missed a period for. Folate deficiency at that single week drives spina bifida and anencephaly, which is why supplementation advice targets everyone capable of pregnancy rather than those already pregnant.
The Standard Dose
Four hundred micrograms daily, from at least one month before conception through the first trimester, is the near universal recommendation, backed by the landmark Hungarian trial and decades of fortification data showing neural tube defect rates falling by a third to a half where folate status improves. Many guidelines extend four hundred micrograms across the whole pregnancy and breastfeeding.
When the Dose Rises
Moderate risk situations, obesity above BMI thirty, preexisting diabetes, and certain seizure medicines that interfere with folate metabolism, commonly earn one milligram daily in UK style guidance. High risk, meaning a previous pregnancy affected by a neural tube defect or a close family history, calls for four to five milligrams by prescription, ten times the standard, started before conception and continued through week twelve.
Food Helps, Pills Close the Gap
Leafy greens, legumes and fortified grains supply folate, but reaching protective blood levels from diet alone is unreliable, and cooking destroys a share. Mandatory flour fortification in over sixty countries quietly cut defect rates wherever introduced, yet supplements remain the dependable layer.
Higher doses belong to medical guidance, since very high folate can mask B12 deficiency and interacts with some medicines. The standard four hundred microgram tablet, cheap and safe, remains one of public health’s best bargains.