The Health Education Authority's campaign, encouraging the use of periconceptional folic acid in the prevention of neural tube defects, started in February 1996 and is ongoing. Its effectiveness was assessed using a questionnaire, answered by patients not exposed to the campaign and by those that were. The study population was comprised of 337 women in approximately their 20th week of pregnancy, attending antenatal clinic for a routine fetal anatomy ultrasound scan. Data were collected on aspects of folate awareness, intake and sources of advice, before and after the campaign's start. Significant increases in preconceptional and total folate consumption, awareness of folate's benefits, and GP prescription were seen as the study went on. Unplanned pregnancy prevented compliance with periconceptional folate guidelines. We conclude that whilst the promotional campaign seemed to work in York, fortification of foodstuffs may need to be used to increase folate consumption in those with unplanned pregnancy.