Apparent prevention of neural tube defects by periconceptional vitamin supplementation. 1981.

An earlier preliminary paper is expanded. Women who had given birth to one or more infants with a neural tube defect were recruited into a trial of periconceptional vitamin supplementation. Two hundred mothers attending five centres were fully supplemented (FS), 50 were partially supplemented (PS), and 300 were unsupplemented (US).

International retrospective cohort study of neural tube defects in relation to folic acid recommendations: are the recommendations working?

Objectives: To evaluate the effectiveness of policies and recommendations on folic acid aimed at reducing the occurrence of neural tube defects.

Design: Retrospective cohort study of births monitored by birth defect registries.

Setting: 13 birth defects registries monitoring rates of neural tube defects from 1988 to 1998 in Norway, Finland, Northern Netherlands, England and Wales, Ireland, France (Paris, Strasbourg, and Central East), Hungary, Italy (Emilia Romagna and Campania), Portugal, and Israel.