OCs also have been the most studied of any family planning method. The study of OCs continues, with new epidemiologic research reported from around the world.

First introduced in 1960, the pill was the leading contraceptive in the US by 1965 (150). By 1970 an estimated 8 to 10 million US women were using the pill, as were an equal number in other developed countries (355, 434).

In developing countries OCs began to appear in the mid-1960s, but high prices put them beyond the reach of all but a few women (378, 434). In 1967 international donor organizations, led by the US Agency for International Development (USAID) and the Swedish International Development Authority (SIDA), began to make OCs available to developing country governments and international family planning organizations (361, 379). Family planning programs in the developing world then began to supply more women with OCs. By the early 1970s an estimated 20 to 30 million married women in developing countries used OCs (434).

OCs remain popular today. With more than 100 million users, OCs trail only voluntary sterilization and IUDs in worldwide use among married women. Among sexually active unmarried women OCs are the most widely used modern method of family planning.