 For example, using condoms with spermicides the estimated perfect use failure rate would be comparable to the perfect use failure rate of the implant.However, mathematically combining the rates to estimate the effectiveness of combined methods can be inaccurate, as the effectiveness of each method is not necessarily independent, except in the perfect case.If a method is known or suspected to have been ineffective, such as a condom breaking, emergency contraception (ECP) may be taken up to 72 to 120 hours after sexual intercourse.