A condom breaks. No birth control was used. A woman misses 2 or more birth control pills in a row or starts a pack 2 or more days late. A diaphragm slips out of place. A woman is more than 2 weeks late for a contraceptive injection.
Sex occurs unexpectedly and without contraceptive protection.
A woman is raped. Emergency contraception should not be used in place of ongoing, correct use of regular contraceptives because it is less effective and provides no protection for sexually transmitted diseases. The action of EPCs has not been clearly established. Studies have shown that ECPs can inhibit or delay ovulation. It has also been suggested that ECPs may prevent implantation by altering the endometrium.