Published online by Cambridge University Press: 31 July 2008
Since the first rush of publications on IUDs following the start of Tietze's Cooperative Statistical Programme for the Evaluation of IUDs (Tietze & Lewit, 1970) there has rarely been a period in which a report relating to newer, ‘second-generation’ devices has not been published. There are degrees of sophistication in these reports varying from the odd anecdotal reference and highly subjective clinical impression to carefully constructed and evaluated large-scale clinical and field trials. This in itself creates problems, for the carefully constructed trials tend to be reported long after the clinical impressions have been publicized. In some cases the impressionistic information has so affected opinion that the presentation of data from large-scale trials providing greater validity and reliability becomes merely an academic exercise.