OverviewPlanned abstinence is a contraceptive technique in which the user attempts to avoid pregnancy by planning to be abstinent, i.e. refrain from having sexual intercourse.
It is important to note that while the actual act of abstinence is 100% effective at preventing pregnancy and the transmission of STDs, using it as a tool for preventing these things is not 100% effective due to the fact that the user may become overwhelmed by desire for sex and impulsively change her/his mind about abstinence. In this case, planned abstinence has failed as a technique, and another technique will need to be used (generally requiring some preparation) if pregnancy is to be prevented.
It is therefore vital not to assume that planned abstinence by itself is an adequate contraceptive, despite the popularity of the claim that "abstinence is 100% effective". This is only true for the act, not the technique, and is logically equivalent to an airline which immediately changes the ownership of any late flights to a different airline so it can claim all of its flights arrive on time.