Hello Thanks for trusting us with your health concern. I pill is successful in preventing a pregnancy in more than 95 % of cases, when taken within 24 hours, and more than 80 % successful when taken within 120 hours of unprotected sex. So yes, a chance of pregnancy always exists. In addition to that,menstrual delay can occur due to - stress, anxiety, emotional turbulence, weight gain or loss, ingestion of hormonal medications, late nights, erratic eating habits, smoking, drinking etc. Excessive caffeine also can cause spotting. The I pill itself is responsible for menstrual delay, and it can prepone or postpone your normal cycles for upto 7 days. SO that could be the most plausible reason. Conditions such as hypothyroidism, PCOS ( polycystic ovarian syndrome ) ,endometrial hyperplasia etc can cause such spotting also. If you do not have your period for another fortnight, please see a gynecologist and have a thorough internal evaluation - per vaginum and per speculum. ALso hormonal assessment - FSH, LH, TSH, Prolactin, OGTT, DHEAS, Free testosterone, Lipid profile etc. A pregnancy test should be taken if you skip your normal period, or it gets replaced with erratic spotting. Also, random and frequent intake of I pill is not recommended, it will mess up your normal menstrual cycle. All the best. Take care.