Plan B effectiveness

Patient: If I had taken plan b on a Monday and had sex again on Saturday will it neutralize Saturdays sex?

Symptoms: NA

Doctor: Hello,A plan -b medication is to be taken within 72 hrs of intercourse but the efficacy is decreased , the later it i s used. The withdrawal bleed should occur within 7 days post intake of pill , if it doesn’t then you may check for pregnancy on missed period with a urine pregnancy test.I hope i have answered your query,regards