New developments in contraceptive drugs for use by women.

Since the oral contraceptive pill was first marketed in 1959, advances in contraceptive drugs for women have been limited to variations on the theme of oestrogen in combination with progestogen or progestogen alone. Alterations to the pill regimen, new progestogens and new delivery systems have increased choice but while these advances significantly improve acceptability, side effects and risks remain essentially unchanged. New ideas are in short supply. Antiprogesterones offer a new approach with a variety of dose regimens but their development has been seriously hampered by the politics associated with their abortifacient action. Other hormone antagonists as contraceptives seem a long way off. Immunocontraception is still at a very early stage. Genes, whose products are uniquely concerned with reproductive processes, promise new targets but radically new contraceptive drugs for women appear distant.