by the U.S. government and other governments, motivated by demographic concerns. Support was made available for improvements in the delivery of hormonal contraception, as well as for the development of new delivery modalities such as implants and injectables, so that the quality and range of contraceptive options were considerably enhanced. Contraceptive use in the developing world rose from less than 10 percent of couples (31 million) in the early 1970s to current levels of 50-60 percent (446 million) by the late 1980s (United Nations, forthcoming). Use of the technologies emerging from the first contraceptive revolution accounted for the great preponderance of that increase: Despite significant regional differences, as of 1995 most of the world's women who use any contraception are selecting modern contraceptive methods (Guttmacher Institute 1995a).
While currently available contraceptives are obviously adequate for many individuals, there is ample evidence that they can only inadequately respond to the changing structure of contraceptive needs. The character of those needs, as we will discuss in detail in the next chapter, is variable, complex, and different in several important ways from the needs that characterized the period of the first contraceptive revolution. The fact that those needs are presented sequentially in the following paragraphs should not be interpreted as evidence of priority; all are of great importance and each is in some way related to the others.
First, there is the sheer volume of need. Minimum estimates of what is defined as "unmet need" range from 120 million to 238 million women worldwide who are at risk of unintended pregnancy because of nonuse of contraception, misuse, or contraceptive failure (Guttmacher Institute 1995a; Institute of Medicine [IOM] 1995a; Robey et al. 1992). Nearly half of the pregnancies defined as "unintended" in the United States as of 1987 had occurred among the 90 percent of women who were, in fact, using some contraceptive method (Forrest 1994).
Second, there are the 52 million pregnancies that women decide to resolve in abortion, approximately 28 percent of all pregnancies worldwide (Guttmacher Institute 1994; WHO 1994). Somewhere around 21 million of those abortions are performed under unsafe and septic conditions, and the burdens of mortality and morbidity they generate are high (WHO 1994). In the United States, of the 6.3 million pregnancies estimated to have occurred in 1987, over half were unintended at the time of conception and, of those, approximately half ended in abortion (Harlap et al. 1991). In the current array of contraceptive methods, there is no method that is explicitly intended to prevent pregnancy in women who have been exposed to unprotected sex, thereby obviating the possible need to confront the dilemmas of abortion.
Third, there is the high proportion of women who opt for sterilization, now the most used method in most of the world's regions, including the United States