Use of folic acid supplements in the first trimester of pregnancy

Abstract

Folic acid supplementation in the periconceptual period is known to reduce the risk of neural tube defects. High dose supplementation prevents a high proportion of recurrent defects, whilst low doses reduce the risk of first occurrences. The Department of Health advises all women considering pregnancy to take folate supplements for 12 weeks prior to conception and in the first trimester of pregnancy. Surveys of the British population indicate that the uptake of this advice is poor. The aim of the present study was to evaluate the uptake of advice in a group of Northampton women between January and June 2001. A total of 301 Caucasian women were recruited through an antenatal dating scan clinic. The women were aged between 16 and 42 years and completed a questionnaire concerning nutritional supplements prior to and during pregnancy and a five-day food diary, which was used to estimate dietary folate intakes. Of the women 67% consumed folate-containing supplements in the first trimester of pregnancy and 43% reported taking folate before becoming pregnant. Women under the age of 21 years were less likely to take folate supplements than women over the age of 21 years (p=0.007), as were smokers (p<0.001) and women from lower social classes. Mean folate intakes, including supplements, were 511±17μg per day and unsupplemented dietary intakes were 237±5μg per day. Of the women interviewed, 24.5% had folate intakes below the reference nutrient intake for pregnancy (300μg per day). The data supports the assertion that neural tube defects are more likely to be prevented through the fortification of staple foods than through supplementation, but highlights the fact that young women from poor social backgrounds may still require close monitoring and support.