Objective: In November 1993, Dutch health authorities advised that women planning a pregnancy should take folic acid in the periconceptional period to reduce the risk of fetal neural tube defects. In the autumn of 1995 a national campaign was organized to inform women and health care professionals in a systematic way.Methods: We assessed the awareness and behaviour of women at their first or second antenatal visit in two surveys in the spring of 1994 and the autumn of 1995, in order to evaluate the impact of non-systematic information during that period, and to collect baseline data to evaluate the effect of the national folic acid campaign. The two surveys were carried out in the north and the west of The Netherlands.Results: The proportio...