Extensive basic research and clinical trials have in some aspect of reproductive physiology, gyne been conducted on inert and medicated intrauterine cology, or family planning. There is in this volume devices. In the last decade, substantial progress has an attempt to provide a total coverage of current been made in understanding the modes of action progress in medicated intrauterine devices. The and the physiological mechanisms of IUDs - pro volume is intended for a broad readership, includ gress resulting from modern techniques and in ing physicians, medical workers, medical personnel, strumentation in microanatomy, immunology, pa and administrators in family planning. It is hoped thology, endocrinology, biochemistry and biophy that this volume will serve as a stimulus to basic sics. Such studies, however, are scattered in such a scientists and clinicians concerned with intrauterine wide spectrum of journals that the clinician and devices to intensify their research toward better family planner can hardly keep up to date with the contraceptive techniques. advances. An attempt is made in this volume to coordinate physiological and clinical parameters. Little is September 1980 known about the possible role of diet, diseases and environmental factors. E. S. E."

This volume contains a collection of papers based on presentations made at the Reproductive Health Care International Symposium held in Maui, Hawaii, USA, October 1982. The papers evaluate biologic interactions be tween intrauterine contraceptive devices and the host, examine the risks associated with the use of these devices and describe aspects of technical progress in the field. The contributing authors bring their knowledge and expertise from four corners of the world to the readers. The editors wish to express their appreciation to the authors for their valuable contributions, to Carolyn K. Osborn for helpful assistance in editing the manuscripts and to MTP Press for accurate preparation and fine presentation of the material. It is hoped that this volume will serve to expand knowledge and generate further interest among its readers in the dynamic and fascinating field of intrauterine contraception. April, 1984 H.M. Hasson, MD Chicago, Illinois, USA ix 1 Ultrastructure of the decidual response to a progesterone releasing IUD U.M. SPORNITZ. K.S. LUDWIG and M. MALL-HAEFELI INTRODUCTION The ever-increasing world-wide use of the IUD has prompted intensive research into the physiology of its contraceptive action. From these studies it has become clear that the alterations in morphology as well as in the physiological milieu produced by the IUD are manifold and differ greatly with the type of IUD used."