[Oral contraceptives: recent safety studies (author's transl)].

: Considerable research evidence now exists to suggest that the risks of oral contraceptive (OC) use were seriously overestimated in earlier work. Because experimentation in medicine is never possible in the rigorous sense in which it is employed in basic sciences, other sources of information must be substituted. Information on the dangers of OC use has come from anecdotal reports, retrospective case control studies, prospective cohort studies, and statistical analyses of deaths, each source being associated with specific problems of interpretation. Recent findings of the Royal College of General Practitioners, the Walnut Creek Study, and the Oxford Study have suggested a lowered incidence of malignant neoplasms in OC than in IUD or diaphragm users; a reduced incidence of breast cancer although the relationship did not consistently achieve statistical significance, and a reduced incidence of ovarian and endometrial cancer. The risks of cervical cancer among OC users appeared slightly higher but disappeared when sexual behavior was controlled. Despite much concern with the possibility of postpill amenorrhea and perhaps sterility among women discontinuing OC use, it now appears that after 2 years there is no difference in the fertility of women who have discontinued use of OCs, IUDs, or diaphragms. Use of OCs as a contraceptive before pregnancy does not appear to be associated with fetal malformations, spontaneous abortion, or perinatal mortality, and the inadvertent use of OCs in early pregnancy is apparently associated with only a very slight risk of anomalies. Recent studies of cardiovascular disease risks indicate that the relative risks of cardiovascular disease among OC users have been greatly exaggerated, especially when smoking is taken into account. Various studies of mortality data have failed to establish a link between OC use and excess mortality from cardiovascular disease.