Effectiveness of emergency contraceptive pills

Patient: My bf had sex with me 3-4 days after my last period, and i took postinor 2 ,2 hours after sex , will i be pregnant ??

Doctor: An emergency contraceptive pill  works by preventing ovulation and/or thickening the cervical mucous and thus helps in p preventing pregnancy. Typically it should be taken immediately to upto 72 hours after unprotected intercourse. The earlier the better. Though no birth control measure is 100% effective, emergency contraceptive are around 90% effective in reducing the chances of pregnancy if taken within 24 hours of sex.