The present and future of immunologic approaches to contraception.

A vaccine capable of causing active immunity against one or more key elements of conception would have several advantages over currently available methods of fertility regulation. It would be amenable to mass use, would require only periodic follow-up, and would not require continuous user motivation. Although natural infertility attributable to immunologic factors has been amply documented, the natural mechanism has been only partially delineated. Consequently, researchers trying to develop a workable vaccine are taking various approaches. This report includes a discussion of autoimmune aspermatogenesis, anti-zona pellucida, anti-nonhormonal placenta-specific protein vaccines, and immunization against female and/or early embryonic antigens, including current approaches to the development of an anti-human chorionic gonadotrophin (HCG) vaccine. The potential advantages and disadvantages of the various immunologic methods are discussed, and the author concludes that although the problems associated with present methods of immunologic contraception are substantial they can be resolved.