We found a matchYour institution may have access to this item. Find your institution then sign in to continue.TitleMethodological Issues in Analyzing Time Trends in Biologic Fertility: Protection Bias.AuthorsKey, Jane; Best, Nicky; Joffe, MichaelPublicationAmerican Journal of Epidemiology, 2009, Vol 169, Issue 3, p285ISSN0002-9262Publication typearticleDOI10.1093/aje/kwn302