When should you start taking folic acid?
The baby’s spine starts forming before most women even know they’re pregnant.
Medically reviewed by Dr. Christopher Sterling, obstetrician ·
The short answer
Ideally before you conceive. Take 400 micrograms of folic acid daily while trying to get pregnant and until 12 weeks. Some people — for example with diabetes, a BMI of 30 or more, or a family history of neural tube defects — need a higher prescribed dose.
Why it matters
The neural tube — which becomes the brain and spinal cord — forms in the first 28 days after conception, when many people don’t yet know they’re pregnant.
Taking folic acid during this window greatly lowers the risk of neural tube defects such as spina bifida.
If you’re already pregnant and haven’t started, start now — it still helps.
What to do
- Take 400 mcg folic acid daily from when you start trying until 12 weeks.
- Ask your GP or doctor about a higher 5 mg dose if you have diabetes, sickle cell or thalassaemia, take epilepsy or HIV medicine, or you or your partner have a family history of neural tube defects (UK guidance also includes a BMI of 30 or more).
- Eat folate-rich foods too: leafy greens, beans, lentils, fortified cereals.
Common questions
Is it too late to take folic acid at 8 weeks?
No — start straight away and continue until 12 weeks. It still offers benefit.
Sources
Medically reviewed by Dr. Christopher Sterling, obstetrician, on against the sources above. Guidance can differ between countries — always follow the advice of your own midwife, doctor or pharmacist. Medical disclaimer.
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