Unfortunately, the international interest in family planning has been decreased because of the increased efforts to combat AIDS and other infectious diseases, as well as by ideological battles.  The proportion of international population assistance funds that went to family planning fell to just 6 percent in 2008, down from 55 percent in 1995, while spending on H.I.V./AIDS represented 74 percent of the total in 2008, up from just 9 percent in 1995, according to Rachel Nugent, a professor of global health at the University of Washington, who cited figures from the United Nations Population Fund.

“Family planning kind of faded from the radar screen, and now it is coming back,” said John May, a visiting fellow at the Center for Global Development and author of a book, “World Population Policies: Their Origin, Evolution, and Impact.”

“There is a realization from many different places that population issues are not going away,” he said.

Although financial support for family planning has faced several international barriers, about $4 billion is expected to be pledged at the London conference to provide family planning services to 120 million women from the world’s poorest countries over the next eight years. The need for this support has increased because of fears that population growth in the developing countries will be multiplied by three later on this century according to the latest estimates, which makes finding a solution for this problem a necessity.

Birth control reduces health risks, the researchers said, by delaying first pregnancies, which carry higher risks in very young women; cutting down on unsafe abortions, which account for 13 percent of all maternal deaths in developing countries; and controlling dangers associated with pregnancies that are too closely spaced.