Hi Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concern... Delay in periods is a common side-effect after intake of an emergency contraceptive pill like postinor 2. The delayed periods are due to effect of high dose of levnorgestrel hormone in postinor 2 pill which disrupts your normal menstruation & causes delayed periods. Your periods may be delayed for 1-2 cycles. An emergency contraceptive pill prevents pregnancy by inhibiting implantation of fertilized egg on to uterus. It is 95% successful if taken within 24 hours of having sex. As you had taken the emergency contraceptive pill within 24 hours of sexual intercourse, pregnancy possibility should be very less. An emergency contraceptive should not be used as regular method of contraception. Regular intake of emergency contraceptive pill could cause irregular & delayed periods, ovarian hyperstimulation syndrome & other harmful effects including infertility. Next time use regular contraceptive pill or condoms for prevention of unwanted pregnancy. You should also undergo a pregnancy test to rule-out pregnancy possibility, however chances of that should be very less. Refer to a gynaecologist for more queries Don t worry you would be fine Hope this information helps