Terms

First let's start with some basic definitions. For example what exactly is meant by the word "contraceptive" and how is the mode of action different from an interceptive? Some women worry that an IUD (intrauterine device) works by causing an abortion which of course is not the case. IUDs work mainly because the spermicidal effect of copper stops the sperm and the egg meeting - that is, as a contraceptive.   

Contraceptive

A contraceptive works by stopping the sperm and the egg meeting up and so prevents fertilization. One example of a contraceptive method is the condom. Other examples are: combined pill, IUD, Depo Provera, diaphragm, vasectomy, tubal ligation. 

Interceptive 

An interceptive is a method that stops pregnancy occurring after fertilisation occurs but before implantation of the fertilized egg in the uterus. An example of an interceptive would be the post coital IUD. As can be seen from the answer to the last question, the IUD mainly works as a contraceptive. However occasionally if sperm do get past to meet the egg ,then the IUD in the uterus helps to prevent implantation occuring - the fertilized egg gets washed out.  Here it is working as an interceptive. Also when the IUD is inserted postcoitally, as an emergency contraceptive, it is also working as an interceptive. 

Abortifacient

Anything that causes displacement of the fertilized egg after implantation occurs is an abortifacient - that is, causing an abortion. An example of an abortifacient is RU486 or Mifepristone. You need to be aware that when Mifepristone is used along with a prostaglandin for medical termination of pregnancy , the same laws pertain as for women seeking a surgical termination.