Plan B
                                            
                                                                                                    Levonorgestrel
                                                                                            
                                        
                                        Plan B, commonly known as the "morning-after pill," is used as a form of emergency contraception to prevent pregnancy after unprotected sex or failed contraception. It contains levonorgestrel, a synthetic hormone that helps prevent ovulation or fertilization, but it is not effective if a pregnancy has already begun.