THE FORM AND STRUCTURE OF INTRAUTERINE CONTRACEPTIVE DEVICES AND DELIVERY SYSTEMS IN RELATION TO THEIR CLINICAL COMPLICATIONS

Abstract

This thesis is based on data from 10,055 IUD insert ions performed by the staff of the Department of Obstetrics and Gynaecology, National University of Singapore between the years 1974-1988. The study involves 25 clinical trials and 16 different IUDs with additional reference to 7 devices which have been subsequently used by the Department. The core of the thesis is to relate the form and structure of IUDs to their clinical complications. However a large number of variables are present, not only with IUDs and their insertion systems, but also with patient variation, pre- and post-insertion factors, physician skills at insertion and the pervading attitude of both physicians and the lay public to IUDs at any time. In the randomized prospective trials only the MLCu250 anrl MLCu375 were basically of the same design and structure (differing only by the copper load and thickness of the wire). However in the combined data set the IPCS/INCS devices shared the same insertion ion system and external morphology (differing only in the progestin content) whilst the NTCu200Ag and NT-LNg(46)20 both utilized the basic Nova T platform and inserter. Cumulative single decrement rates have been calculated for the standard IUD termination categories and significant differences between devices are highlighted. Of the devices tested the TCu380Ag and the NT-LNg(46)20 had the lowest pregnancy rates but the two Multiload devices had significantly less use-related complications over the first 2 years of use. In general the copper devices were superior to the inert devices. Among the copper devices the 7Cu200 had the poorest efficacy and the most use-related terminations. The NT-LNg(4L)20 was clearly superior to the other three progest in-releasing devices but the incidence of other medical terminations were relatively high. Some difficulty arose in the classification of the Latex Leaf, Dalkon Shield and OMGA devices since the part played (if any) by their bioactive elements is poorly defined. Of these three devices, the OTl(Cu) proved to have significantly more terminations than nearly all the other IUDs tested, including pregnancies, expulsions and removals for pain/bleeding. Certain 'rare events'such as ectopic pregnancy, pelvic Inflammatory disease and translocation of the IUD are particularly important as clinical complications of IOD use. These are discussed in separate chapters and correlated to IUD form and structure. IUDs provide safe and highly effective contraception for many women. Unfortunately adverse publicity in both the lay and medical press has limited their use in many countries. Large data sets from different communities and lifestyles are needed to evaluate which IUD features enhance efficacy or reduce clinical complications. The author believes that the data from this thesis makes a significant contribution to the available literature.