'Just take folic acid.' It's probably the most consistent piece of advice women get when they start thinking about pregnancy. From their GP, from the pharmacist, from every prenatal on the shelf.
And look, the intention behind it is right. Folate is critical in early pregnancy.
And honestly, the bit that almost never comes up is that folic acid and folate aren't the same thing. For a lot of women, the form it comes in is critical.
So what's the difference?
Folic acid is the synthetic version. The body can't use it straight away. It goes through a conversion process first, ending up as 5-MTHF, which is the active form. One of those conversion steps depends on an enzyme called MTHFR, and this is the part that catches a lot of people out.
Somewhere between 30 and 50% of Australians carry a variant of that gene that slows the whole process down. One copy and the enzyme runs at around 65%. Two copies and you're looking at roughly 30%.
And unless you do more extensive testing, it's hard to know if you are a carry or not, as there are no symptoms. Most people find out incidentally, usually through fertility investigations or after recurrent pregnancy losses.
So if your MTHFR enzyme is running at 30%, a chunk of the folic acid you're taking every day isn't converting. It's just sitting there unmetabolised- and this can disrupt fertility.
Why this matters before you even have a positive test
The neural tube closes around day 28. That's your baby's brain and spinal cord forming, usually before most women have taken a test. Folate needs to already be there at adequate levels for that window. If conversion has been impaired and levels aren't where they need to be, it can influence the viability of the pregnancy.
What about all the folic acid research?
The original research linking folic acid to neural tube defect prevention is solid and still stands. The issue isn't whether it works, it's that not everyone can metabolise it. Methylfolate skips the conversion step entirely. It's already active, so it works the same way for everyone, regardless of which MTHFR variant they carry.
So why isn't there the same volume of trial data for methylfolate? Those original studies were done decades ago, and you couldn't run them today. Withholding folate from pregnant women wouldn't get through an ethics review now. The gap in data reflects when the research was done, not a gap in effectiveness.
Worth knowing for men too. MTHFR variants affect both partners, and folate status influences sperm health as well.
Do you need to test for MTHFR before trying to conceive?
Most people don't need to test. It typically comes up after recurrent losses, as one piece of a bigger picture. For everyone else, choosing a prenatal that already contains methylfolate covers it without needing a result first.
What to look for
On the folate line of any prenatal label, look for levomefolate glucosamine, L-methylfolate or 5-MTHF. Both Nuri's Prenatal Support [Her] and Prenatal Support [Him] use levomefolate. It's one of the decisions we feel most strongly about in the formulation.
This is general information only. If you have a history of recurrent pregnancy loss or are on other medications, please speak with your GP about your specific folate needs.