Prevention of pregnancy is recommended in the following cases: Rape; Failure of a usual contraceptive method, uncorrected contraceptive method or in emergency cases, eg., Condom rupture, miscalculation of periodic abstinence method, diaphragm or cap dislodgement, breakage or early removed, IUD expulsion, missed parenteral contraceptive or missed regular oral contraceptive pills for three or more days in a cycle.