a b s t r a c t
Since the mid-1990s, governments and health organizations around the world have adopted policies
designed to increase women’s intake of the B-vitamin ‘folic acid’ before and during the first weeks of
pregnancy. Building on initial clinical research in the United Kingdom, folic acid supplementation has
been shown to lower the incidence of neural tube defects (NTDs). Recent debate has focused principally
on the need for mandatory fortification of grain products with this vitamin. This article takes a longer
view, tracing the transformation of folic acid from a routine prenatal supplement to reduce the risk of
anaemia to a routine ‘pre-conceptional’ supplement to ‘prevent’ birth defects. Understood in the 1950s
in relation to social problems of poverty and malnutrition, NTDs were by the end of the century more
likely to be attributed to individual failings. This transition was closely associated with a second. Folic
acid supplements were initially prescribed to ‘high-risk’ women who had previously borne a child with
a NTD. By the mid-1990s, they were recommended for all women of childbearing age. The acceptance of
folic acid as a ‘risk-reducing drug’ both relied upon and helped to advance the development of preventive
and clinical practices concerned with women’s health before pregnancy.