Milestones in intrauterine device development

Abstract

The IUD has undergone numerous modifications and innovations since the Graefenberg ring of the early 1900s. This and the other small rings were initially designed so as to introduce a foreign body of minimal size into the uterine cavity. Larger plastic devices, introduced in the 1960s (e.g., Lippes Loop, Birnberg bow, Margulies Spiral), were purported to have lower pregnancy and expulsion rates. Monofilament tails were also added because the ease of detection and extraction of the IUD allowed by the tail was felt to be more important than the risk of potential infection. With the development of the Dalkon Shield in the late 1960s came a new era in IUD development. The A.H. Robins Company, developers of the Shield, elected to add a sheathed multifilament tail which, over the next 4 years, resulted in 242 spontaneous midtrimester septic abortions in women wearing the Shield; only 37 women not wearing a Dalkon Shield experienced this event. 10 maternal deaths resulted. Salpingitis and pelvic inflammatory disease (PID) were other serious results of IUD wear. Consequently, IUD use in the US and worldwide dropped. Of major import was the finding that, when compared to noncontraceptors, the relative risk of PID was 15.6 for longterm Dalkon Shield users and only 1.5 for longterm users of other types of IUDs. When Dalkon Shield data are extracted, there remains a very low rate of serious complications resulting from IUD wear. The problem with the Dalkon Shield has encouraged more research in the direction of the tailless IUD. The development of the small T-shaped IUD came as an attempt to have a device which was adapted to the size and shape of the uterine cavity rather than the other way around. To this was added copper to enhance the contraceptive effect. Copper-medicated IUDs, among them the Copper 7, Nova-T, and the Multiload, were added to the list of available IUDs. Progestogens have been now incorporated with the plain T. This has resulted in the Progestasert and the Levonorgestrel T, both of which effect a reduction in menstrual blood loss. While major advances have been made in the field of intrauterine contraception, more innovations and improvements can be expected in the future.