The condom broke on us on the 17th day of my cycle (which is usually about 26 days) and took the pill approximately one hour after it happened. I checked the box to see if the timing of a woman's cycle is also a factor of its effectiveness, but I didn't find much info about it. The clues I got were "It may interfere with fertilization of an egg, and it may prevent implantation of a fertilized egg". The word "may" does not ease my stress and fear, and it worries me that the box, along with the website, chooses to be silent on this statistic... Any help is appreciated.