Contingency one can prevent pregnancy after a contraceptive accident (such as a broken condom) or when no form of birth control was used. Treatment is most effective if used in the first 72 hours (3 days) following unprotected sex.
Contingency one cannot terminate an existing pregnancy. Although there is no scientific evidence that Contingency One would harm a developing embryo, women who are already pregnant should not use this product. Contingency One should not be used in place of regular contraception. It does not work as well as most other contraceptives used correctly.