Neural‐tube defects and vitamins: the need for a randomized clinical trial

Abstract

It has been suggested that taking extra vitamins around the time of conception may reduce the risk of fetal neural‐tube defects. We have examined the evidence for this and conclude that there is considerable doubt about the efficacy of such a regimen. Also, it cannot be assumed that the taking of extra vitamins has no adverse medical effects. We give reasons for our view that a large randomized clinical trial is ethical and the only satisfactory way of resolving the matter. The Medical Research Council is currently conducting such a study in centres in Britain and abroad, involving women who have already had a pregnancy with a fetal neural‐tube defect. The design of the Medical Research Council study is described briefly.