Abstract

Although intrauterine devices (IUDs) are not as effective as the best oral contraceptives, many women prefer them, and they may be a first choice for women for whom the pill is contra-indicated. During the six years since we last discussed IUDs,¹ both their design and the methods of analysis of IUD clinical trial results have improved considerably. Devices produced since 1966 differ from previous ones in composition and shape and in the method of insertion into the uterus. The ‘M’ device,² the Dalkon Shield³ and the Gravigard⁴ have all resulted from interdisciplinary collaboration involving bioengineers. Two centres in the United States^{5 6} are assessing bioengineering aspects of the interaction between IUDs and the uterine musculature.