The world’s population is getting older, slowing down and may stop growing completely by 2100.

Women are having fewer babies, the number of elders is rising fast and an increased number of countries face population declines, according to a projection of world population trends released Monday by the United Nations.

The global population of 7.7 billion will increase to 9.7 billion by midcentury and may peak at 10.9 billion by around 2100, the United Nations said. The findings are a downward revision from the previous forecast by the global body, when it projected 11.2 billion people would inhabit the planet by century’s end.

John Wilmoth, the director of the population division in the United Nations Department of Economic and Social Affairs, which produces the projections every two years, said earlier findings had implicitly pointed to an end in population growth sometime around the end of the century.

The projection that growth will stall in 2100 is only an approximation, Mr. Wilmoth said in a telephone interview, but “the important point, in all likelihood, is that it will eventually stop growing.”