Live birth rates around the world have almost halved, according to a major study published in the Lancet.
Researchers looked at data from 195 countries and territories between 1950 and 2017.
The findings show that the decline in live births, since 1950, means that nearly half of countries are producing fewer children than are needed to maintain their population.
Researchers say the total fertility rate decreased by 49.4% from 1950 to 2017. This drop was evident in all countries and territories.
The fall in birth rate is more pronounced in regions that are more economically developed.
Better education and access to contraception is also playing a part.
Despite the reduction, researchers say the global population has been increasing by an average of 83.3 million per year since 1985. This growth has been attributed to lower mortality rates.
Researchers stressed the importance of such studies in assisting governments in assessing the national need for infrastructure, housing, education, employment, health care, care of older people, electoral representation, provision of public health and services, food supply, and security.