e-Library of Evidence for Nutrition Actions (eLENA)

Periconceptional folic acid supplementation to prevent neural tube defects

The nutritional status of women prior to and during pregnancy plays a key role in fetal growth and development. Poor nutritional status in a woman in the period before she conceives and in early pregnancy (up to 12 weeks gestation),may increase the risk for adverse pregnancy outcomes. This periconceptional period is therefore considered to be an important time for interventions that promote maternal health and thereby increase the likelihood of positive pregnancy outcomes.

Birth defects, or congenital malformations, are structural or functional abnormalities present from birth and can be caused by a number of factors, including micronutrient deficiencies. Neural tube defects such as spina bifida are one of the most common congenital malformations.

Current evidence suggests that folic acid supplementation in the periconceptional period, either alone or in combination with other vitamins and minerals, can prevent neural tube defects.

WHO recommendations

All women, from the moment they begin trying to conceive until 12 weeks of gestation, should take a folic acid supplement (400 μg folic acid daily).

Women who have had a fetus diagnosed as affected by a neural tube defect or have given birth to a baby with a neural tube defect should:

  • receive information on the risk of recurrence;
  • be advised on the protective effect of periconceptional folic acid supplementation;
  • be offered high-dose supplementation (5 mg folic acid daily); and
  • be advised to increase their food intake of folate.


Additional information can be found in the guidance document under 'WHO documents' below.

WHO documents

WHO documents

GRC-approved guidelines

Status: not currently available

Other guidance documents


Related Cochrane reviews
Other related systematic reviews
Clinical trials