Most TTC checklists put folic acid at the top. But it rarely gets explained why it matters quite as much as it does, or why the timing is actually the whole point.
Why the neural tube changes everything
Folic acid is the synthetic form of vitamin B9, and it plays a central role in DNA synthesis and cell division. Those processes matter most in the earliest days after conception, when the neural tube, the structure that becomes the baby's brain and spinal cord, is forming and closing.
That critical window is the first 28 days after conception. Often before you've even taken a pregnancy test.
This is why both the NHS and ACOG recommend starting folic acid before you begin trying. The NHS recommends 400mcg daily, ideally from at least three months before you start trying, continuing through the first 12 weeks of pregnancy. ACOG recommends 400-800mcg starting at least one month before trying to conceive.
Some women are advised to take a higher dose of 5mg daily: those who have had a previous pregnancy affected by a neural tube defect, who take certain medications including anti-epileptics, or who have a BMI over 30. This is prescribed rather than bought over the counter. If any of those apply to you, speak to your GP before you start trying.
Does folic acid help you get pregnant?
This is a fair question, and the honest answer is: it's not what it's primarily for, but the evidence isn't blank either.
Folic acid is not a fertility drug, and there's no strong clinical trial evidence that taking it increases your chances of conception. But a 2012 cohort study (1) examining dietary folate intake and reproductive function in premenopausal women found that those with higher folate intake were more likely to have regular ovulatory cycles. There's also emerging research suggesting that adequate folate levels support healthy follicular development.
What that tells us is that low folate may create a less favourable environment for conception. Supplementing on top of already adequate levels is not a proven fertility booster. The primary reason to take it remains what it has always been: being ready for the moment pregnancy begins.
What about your partner?
The evidence on folate and male fertility is genuinely mixed. A large 2020 randomised trial (2) involving over 2,000 men found that supplementing with folic acid and zinc for six months did not improve live birth rates or sperm quality, and on that basis folic acid is not currently recommended for male partners by the NHS.
A 2021 trial (3) found a different picture specifically in men with confirmed male factor infertility undergoing IVF-ICSI: high-dose folic acid reduced sperm DNA fragmentation and was associated with higher biochemical pregnancy rates. The two studies differed in dose, population, and context. For men in the general TTC population without a diagnosed fertility issue, supplementation is not currently supported by the evidence. For those with confirmed male factor infertility preparing for IVF-ICSI, it's worth raising with a specialist.
Which form should you take?
Standard folic acid at 400mcg works for most women trying to conceive. If you're wondering whether to take folic acid, folate, or methylfolate instead, that's a slightly different question with its own nuances around absorption and genetics. We're covering it in next week's post.
The bottom line
If you're trying to conceive and not already taking folic acid, start today. The neural tube closes long before most people know they're pregnant, and adequate folic acid levels need to already be there when that window opens. It's one of the most evidence-backed steps you can take when trying to conceive, and the timing is everything. Join our waitlist to be the first to try PregSafe.
PregSafe is not a replacement for medical advice. Always consult your healthcare provider for personalised guidance.
Sources
(1) Gaskins AJ, Mumford SL, Chavarro JE, Zhang C, Pollack AZ, et al. The impact of dietary folate intake on reproductive function in premenopausal women: a prospective cohort study. PLOS ONE. 2012;7(9):e46276.
(2) Schisterman EF, Sjaarda LA, Clemons T, et al. Effect of folic acid and zinc supplementation in men on semen quality and live birth among couples undergoing infertility treatment: a randomized clinical trial. JAMA. 2020;323(1):35-48.
(3) Mathieu d'Argent E, Ravel C, Kolanska K, et al. High-dose supplementation of folic acid in infertile men improves IVF-ICSI outcomes: a randomized controlled trial (FOLFIV Trial). Journal of Clinical Medicine. 2021;10(9):1876.
