"The cervical cap is an ancient method of contraception revitalized during the 1970s by feminist health care practitioners. It acts as a contraceptive both mechanically and chemically. This study looks at the effectiveness and satisfaction of the cervical cap in 76 women fitted over a 1-year period. The cap is 80.4% effective according to the Pearl Index and 89% of the women are satisfied with using the cap. There is a 51 % continuation rate over a 1-year period. The cervical cap appears to have a satisfactory rate of contraception when compared with other barrier methods and women are adept at its use. A significant finding is that most pregnancies occur in the first three months of cap use. A much higher effectiveness is seen subsequently."
January 1, 1970
https://en.wikiquote.org/wiki/Cervical_cap