Hormonal contraception: state of the art and future perspectives.
Attempts at controlling female fertility through the utilisation of hormonal extracts date back to the beginning of the 20th century, however, practical applications in the human species were only possible when Gregory Pincus had the excellent idea of mimicking the effect of progesterone in blocking ovulation and, through this mechanism, inhibit fertility. It is important to notice that, over its 50 years of history, the original method for hormonal contraception (HC), universally known as ''the pill'', developed into a variety of modalities that today utilise a number of new routes of administration. HCs of today are exclusively made up of either oestrogen-progestin combinations or progestins alone. This does not mean that no attempt has been made to use other classes of steroids for contraception. The best known compounds tested are the so-called ''antiprogestins'', more precisely called selective progesterone receptor modulators (SPRM). Hormonal contraceptives, originally administered in the form of daily pills, can be utilised today through seven different routes: intramuscularly, intranasally, intrauterus, intravaginally, orally, subcutaneously, and transdermally. New strategies in the field of oral contraception include further dose reduction, the synthesis of new active molecules and new administration schedules. Newly marketed contraceptive rings to be inserted in the vagina, offer a novel approach by providing a sustained release of steroids and low failure rates. The transdermal route is now well established, as a contraceptive patch, a spray or a gel. The intramuscular route has also seen new products with the marketing of improved monthly injectable preparations, containing an oestrogen and a progestin. A new minipill (progestin-only preparation) containing desogestrel has been recently marketed in a number of countries and is capable of inhibiting ovulation in most women. After the first device capable of delivering progesterone directly into the uterus was withdrawn, a new system releasing locally 20 microg over 5 years, is today widely marketed with excellent contraceptive and therapeutic performance. Finally, several subcutaneously implanted systems have been also developed in the form of contraceptive ''rods'', where the polymeric matrix is mixed with the steroid and ''capsules'', made of a hollow polymer tube filled with free steroid crystals. Last, but not least, work is in progress to provide effective emergency contraception after an unprotected intercourse. Very promising in this area is the use of SPRM.
Benagiano
G
G
Department of Gynaecological Sciences Perinatology and Child Care, La Sapienza University, Rome, Italy. giuseppe.benagiano@uniroma1.it
Bastianelli
C
C
Farris
M
M
D000281:Administration, Intranasal; D000282:Administration, Intravaginal; D003267:Contraception / Q000379:methods* / Q000639:trends; D003271:Contraceptive Agents, Female / Q000737:chemistry / Q000627:therapeutic use*; D003280:Contraceptives, Oral, Synthetic / Q000627:therapeutic use; D017135:Desogestrel / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D004967:Estrogens / Q000627:therapeutic use; D005193:Family Planning Services / Q000379:methods / Q000639:trends; D005260:Female; D006801:Humans; D007271:Injections, Intradermal; D007273:Injections, Intramuscular; D007279:Injections, Subcutaneous; D007434:Intrauterine Devices; D011372:Progestins / Q000037:antagonists & inhibitors; D016896:Treatment Outcome
D003271:Contraceptive Agents, Female; D003280:Contraceptives, Oral, Synthetic; D004967:Estrogens; D011372:Progestins; D017135:Desogestrel