Hello dear Understand your concern As took I pill with in 24 hour after sex, success rate to prevent the pregnancy is high around 95 percent. But there may be failure rate around 5 percent. 5 percent chance of pregnancy. But may be slight less as semen was not ejaculated inside the vagina. After taking I pill, your period may be delayed/earlier. So if period will be delayed by 12-14 days then you have to confirm the pregnancy by using home pregnancy kit and or by Blood HCG. If pregnancy will come positive then still you can terminate the intrauterine pregnancy by abortion pills under the advice of gynecologist. Hope this may help you Best regards Dr. Sagar