Wald N J, Polani P E
Br J Obstet Gynaecol. 1984 Jun;91(6):516-23. doi: 10.1111/j.1471-0528.1984.tb04796.x.
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.
有人提出在受孕前后额外补充维生素可能会降低胎儿神经管缺陷的风险。我们已对此证据进行了研究，并得出结论：对于这种方案的有效性存在很大疑问。此外，不能假定额外补充维生素没有不良医学影响。我们给出了理由支持我们的观点，即进行大规模随机临床试验是符合伦理道德的，也是解决该问题的唯一令人满意的方法。医学研究委员会目前正在英国和国外的多个中心开展这样一项研究，参与对象为那些曾有过胎儿神经管缺陷妊娠经历的女性。简要介绍了医学研究委员会这项研究的设计。
