Between now and the year 2000 many more new contraceptives or significant improvements in current methods could emerge. The possible new contraceptives can be categorized as follows: methods that are almost here, that is, they are already available for routine, nonexperimental use in at least 1 country and are likely to be more widely available soon; methods that are likely to be available soon, i.e., methods at the advanced field testing stage; and possibilities, i.e., methods currently undergoing animal studies or in early trials in humans. Additionally, many other methods have been suggested on the basis of current understanding of reproductive function, but work to develop an actual method has not yet begun. The category of almost here methods includes: longer lasting copper IUDs, with lifespans of 6-20 years, are being developed in several designs, namely, the TCu-220c, the TCu-380a and TCu-380Ag, and the Nova T; the Norplant implant, a set of flexible plastic capsules inserted under the skin of a woman's forearm; a wider choice of injectables may emerge, with once-a-month types, which are already available in some Latin American countries, Spain, and China, joining the more widely available longer acting injectables Depo-Provera and Noristerat; and the spermicidal sponge. The category of likely methods includes: T-shaped IUDs that release the progestin levonorgestrel; and hormone-releasing vaginal rings. Finally, the category of possible methods includes: chemicals for voluntary sterilization, which might be used to permanently block the vas deferens in men or the fallopian tubes in women; chemical plugs for the fallopian tubes; weekly and monthly hormonal pills; gossypol, the male oral contraceptive (OC) made from the cotton plant; a highly accurate test that couples could use by themselves to predict when ovulation will occur; various new spermicidal agents; biodegradable implants; a possible new type of injectable which consists of extremely tiny biodegradable capsules that release hormone at different speeds; new chemicals that imitate or block the action of luteinizing-hormone releasing factor; a self-administered method to insure that menstruation occurs; a long acting hormonal method for men which would work by lowering the sperm count; and a vaccine to prevent pregnancy. The challenges of these new methods involve service delivery, logistics, information, education and communication. Research on new contraceptive methods cannot stop when the method leaves the hands of its developers. Surveillance of users' health and follow-up with epidemiologic research are needed.

作者：W, Rinehart

来源：Asian-Pacific population programme news 1984 年 13卷 4期