Hi, Emergency contraceptive contains high dose of hormones. These when taken within 72 hours of sex (earlier the better) postpone ovulation and prevent pregnancy due to particular sex. As a side effect they cause delay in upcoming menses. If such contraception is used repeatedly, it may cause temporary irregularity in periods. But emergency contraceptive does not cause PCOD. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Vasudha Jayant Athavale, General & Family Physician