The world economy would be boosted by billions of dollars if all women had access to contraception, the United Nations said on Wednesday in its annual State of World Population report.
The report said inadequate family planning in developing countries contributed significantly to poverty and ill health, and that $5.7 billion (4.5 billion euros) could be saved by preventing unintended pregnancies and unsafe abortions.
"Family planning is not a privilege, but a right. Yet, too many women—and men—are denied this human right," said Babatunde Osotimehin, executive director of the UN Population Fund (UNFPA).
"The data that we have shows that access to family planning unlocks unprecedented rewards, both at the individual and national level," the former Nigerian health minister told a press conference in London.
"Women who have access to family planning can contribute enormously to economic development. The accumulated effect of these highly personal decisions can influence entire countries and regions."
Around 222 million women currently have insufficient access to contraceptives, the UN report estimated.
It described "an array of economic benefits" brought by family planning, including a rise in the number of women in the workforce and wealthier households as the number of children in each home decreases.
But it noted that global funding for family planning has declined and said an extra $4.1 billion would be needed each year to fund contraceptives for everyone who needs them in developing countries.
The UN cited one study that attributed a third of the growth in the Asian "tiger" economies to increased use of contraceptives, which caused a drop in the number of children dependent on every working adult.
If an additional 120 million women who wanted contraceptives could get them by 2020, the report said, an estimated three million fewer babies would die in their first year of life.
A woman's chances of dying in childbirth were cut by a third by access to birth control, Osotimehin added.
"Thirteen percent of maternal mortality around the world is due to unsafe abortion," he told journalists. "That, in many circumstances, occurs in people who want family planning and they don't get it."
The report said that access to family planning was a "fundamental human right" that governments had an obligation to protect.
Osotimehin described contraception as "one of the most effective means of empowering women", but he added that the right to birth control did not necessarily include the right to abortion in all countries.
"Abortion should not be promoted as a method of contraception. Where it is legal, we advocate that it should be done safely," he told AFP.
Africa and South Asia were the regions with the worst access to contraception, he added, "essentially because of poverty."