OBJECTIVES: Studies show that periconceptional folic acid supplementation can prevent some neural tube defects, the most common birth defects contributing to infant mortality and severe disability. Despite widespread campaigns to promote folic acid supplementation for women of childbearing age, a recent national Gallup survey found only 29% of women reported taking a multivitamin containing folic acid. The rate of supplementation is even lower among women with lower incomes and education. The objective of this pilot study is to determine the effectiveness of direct-to-consumer strategies targeted to increase folic acid use among women of childbearing age in a Medicaid managed care plan. METHODS: A total of 2400 English-speaking women (18-45 years old) enrolled in CareOregon were randomly selected to receive one of 3 interventions: 1) folic acid educational material plus a sample of multivitamins containing folic acid and a voucher to redeem by mail for multivitamins; 2) educational material plus a voucher to redeem by mail for multivitamins containing folic acid; and 3) educational material only. Vitamins were sent free of charge to subjects through a mail-order pharmacy. Pre-and 3 month post-intervention surveys were used to assess subjects' folic acid use and knowledge. Prescription claims for multivitamins and folic acid were evaluated before and after intervention. RESULTS: The combined pre- and post-intervention survey response rate for the 3 groups was 16.1%, 13.2%, and 11.9%, respectively. The reported mean folic acid supplement use for the 3 groups before intervention was 43%, 46%, and 37%, respectively, and 59%, 62%, and 37%, respectively, after intervention. Folic acid supplement use increased significantly (p<0.01) for the voucher and vitamin groups, but not for the educational material only group. CONCLUSIONS: Providing easier access to multivitamins through direct marketing significantly increases folic acid supplement use after three months in women in a Medicaid population.