Folic Acid and Pregnancy
NICE guideline [NG247] Maternal and child nutrition: nutrition and weight management in pregnancy, and nutrition in children up to 5 years. Published: Jan 2025.
NICE CKS Pre-conception – advice and management: Scenarior: Pre-conception advice for all women. Last revised: Jun 2025.
Guidelines
Overview of Pregnancy and Supplements
NICE recommends taking the Healthy Start vitamins (free supplements provided by the NHS to eligible pregnant women) that contain:
- Folic acid 400 micrograms
- Vitamin C 70mg
- Vitamin D 400 IU
Vitamin A supplementation is not recommended during pregnancy.
Pregnant women should avoid taking supplements containing vitamin A (retinol) and should not eat liver or liver products, as these contain high levels of vitamin A. Excess vitamin A during pregnancy has potential teratogenic effects.
Folic Acid and Pregnancy
Indications
- ALL women who are planning pregnancy → take before attempting
- ALL women who are already pregnant → take ASAP
It is best practice to start folic acid BEFORE conception.
This is because the neural tube closes within the first 4 weeks of gestation, starting folic acid only after a +ve pregnancy test may miss this crucial window for neural tube defect prevention.
It is important to still take folic acid supplements even if food (including flour) is fortified with folic acid.
Duration
Folic acid should be taken from whenever started (ideally pre-conception) until 12 weeks of pregnancy
Folic Acid Doses
Standard dose: folic acid 400 micrograms (not mg!) daily
High-dose folic acid 5mg daily should be offered to those at increased risk of having a baby with neural tube defect or other congenital malformation:
- Partner with neural tube defect
- Personal family history of neural tube defect
- Previous pregnancy with a neural tube defect
- Diabetes (1 and 2)
- Sickle cell anaemia and thalassaemia
- Taking anti-epileptic and HIV medicines
Overweight / obesity used to be an indication for high-dose folic acid. However, this alone is no longer an indication.
Reassure anyone with a body mass index (BMI) of 25 kg/m2 or more who is planning to become pregnant or is in the first 12 weeks of pregnancy that they do not need to take more than 400 micrograms of folic acid a day, unless they have any of the factors listed in recommendation 1.1.5.
References