"i was sure i was ovulating when the condom broke, but i took plan b 9 hours after the incident. i read on the planned parenthood website that if you are ovulating or have already ovulated, plan b has no effect in preventing pregnancy. luckily, i got my period on the exact day that i was supposed to. i rated 10 stars because if taken before ovulation, it is very effective as it mainly works by delaying ovulation. however, during or after ovulation it&#039;s not clear that it works to prevent pregnancy. i didn&#039;t get pregnant, and it may be because plan b did it&#039;s job in preventing implantation, or it could have been because i was not actually ovulating. it is difficult to tell when exactly you are ovulating. don&#039;t freak out just yet. good luck!"