在资源贫乏且通常有维生素 A(视黄醇)缺乏症的国家,特别是孕妇,初级预防可能有效。[8]McCauley ME, van den Broek N, Dou L, et al. Vitamin A supplementation during pregnancy for maternal and newborn outcomes. Cochrane Database Syst Rev. 2015;(10):CD008666.http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD008666.pub3/fullhttp://www.ncbi.nlm.nih.gov/pubmed/26503498?tool=bestpractice.com[14]Radhika MS, Bhaskaram P, Balakrishna N, et al. Effects of Vitamin A deficiency during pregnancy on maternal and child health. BJOG. 2002;109:689-93.http://www.ncbi.nlm.nih.gov/pubmed/12118649?tool=bestpractice.com[15]Mayo-Wilson E, Imdad A, Herzer K, et al. Vitamin A supplements for preventing mortality, illness, and blindness in children aged under 5: systematic review and meta-analysis. BMJ. 2011;343:5094http://www.bmj.com/content/343/bmj.d5094.longhttp://www.ncbi.nlm.nih.gov/pubmed/21868478?tool=bestpractice.com