[Levonorgestrel. The day-after pill].

Only making use of Levonorgestrel as a post intercourse anti-conceptive method has proven to be more effective than prior methods and is the object under study in this report. This post intercourse anti-conceptive consists of a set of methods which, employed after at risk sexual intercourse and within a maximum period of time, avoid pregnancy. This post intercourse anti-conceptive is not considered to be an abortion method but it should not be used as a habitual anti-conceptive method due to its adverse effects and its numerous interactions with other pharmaceutical products.