Norethindrone is a synthetic progesterone derivative that works in the case of Antifertility drugs. The exact mechanism behind which has been stressed upon in Antifertility Drugs – Definition and Benefits. This page has elaborated upon what antifertility drugs are and has everything written in a simple, lucid language so that the students make sense of the content. This page has been designed by Science teachers who know exactly how much to include in the chapter on Antifertility Drugs. All students who read from this page will be able to relate.