The Oxford-Family Planning Association contraceptive study involves over 17 000 women who were recruited at 17 clinics in England and Scotland during the interval 1968-74 and have been followed up ever since. This paper describes the survey methods, the characteristics of the participants, the progress of the study, the main results and publications to date, and the proposals for future work. Although the study was originally mainly concerned with the benefits and risks of oral contraceptives it has, in fact, contributed to knowledge about a wide variety of birth control methods. The data on efficacy are of special value in that they cover all methods of contraception in common use and have been derived from a homogeneous and closely observed population. The mortality figures, while limited in extent, have supplemented the findings in the Royal College of General Practitioners study. Reports on morbidity from many different diseases have been published; these have documented both beneficial and harmful effects of various contraceptive methods. The study data on return of fertility after discontinuation of contraception are unique, while contributions have also been made to knowledge about outcome of pregnancy in those stopping contraception to have a planned baby or becoming accidentally pregnant while using a birth control method. The study, which is supported by the Medical Research Council, is currently funded until mid-1989.
PIP: This article updates progress and results to date in the Oxford Family Planning Association contraceptive study. This study involves over 17,000 women recruited at clinics in England and Scotland in 1968-74 who have been followed since then. At entry to the study, 56.6% of subjects were oral contraceptive (OC) users, 24.8% were diaphragm users, and 18.6% were IUD users. By the end of 1983, 192,000 woman-years of observation had been collected. Over 4000 women currently have at least 8 years of OC use, providing opportunities for a study of longterm and delayed effects of this contraceptive method. The data suggest changing patterns of contraceptive use over time, with a decline in OC use and a rise in the use of sterilization as subjects have aged. Progestogen-only OCs are moderately popular across the age range, but combined OCs are rarely use past the age of 40 years. Although the study was originally concerned with the risks and benefits of OC use, it has contributed to knowledge about the effects of a wide variety of contraceptive methods. In addition, it has been possible to analyze the influence of factors such as age, parity, social class, and motivation on contraceptive efficacy. 33 individual publications (listed and annotated in the article) have emerged from the study. Work is currently underway on factors affecting fertility, psychiatric illness in users of different methods, patterns of cervical cytology in women with neoplasia of the cervix uteri, the effectiveness of IUDs in women with arthritis, and the realtionship between OC use and chronic inflammatory bowel disease. Future research will focus on the delayed effects of OCs on major chronic diseases such as cancer, coronary heart disease, and diabetes. The study is funded through mid-1989.