Pharmacological female contraception: an overview of past and future use.

Female hormonal contraceptive methods have undergone slow change over the past four decades. Due to social, political and legal reasons, as well as medical complications, several new methods have been removed from the contraceptive armamentarium almost as quickly as they have been added. With worldwide unintended pregnancy rates approaching 50% of all pregnancies, there is an increased need for the development of new methods of effective, safe, acceptable hormonal contraception. Pharmacological methods of contraception are reversible and contraceptive steroids are now formulated in pills, patches, intravaginal rings, subdermal implants and injections. All currently marketed formulations are made from synthetic steroids and contain no natural oestrogens or progestins. This article reviews the current state of female contraception and explores future directions.