The important thing to consider about emergency contraception is timing. The 'morning after' pill only works if taken within 72 hours of having had unprotected sex. After this , it is rendered usless. Furthermore , the timing of the woman's menstrual cycle must be taken into consideration. If you are mid cycle and require emergency contraception , then a coil is normally recommended as opposed to the pill for greater reliability. It should always be noted that just as no contraception is 100% reliable , nor is any form of emergency contraception. There is a common myth that emergency contraception is a guaranteed certainty to prevent an unwanted pregnancy but there are occasions when yes , it will fail. I'm afraid you wouldn't have a leg to stand on in terms of having a case to sue for an unwanted pregnancy because it is made aware to patients that the pill is not 100% reliable.