Researchers analyzing more than 200 years of data from 237 countries have uncovered a surprisingly consistent pattern behind declining birth rates worldwide. While several governments are searching for ways to reverse falling birth rates, Itao cautioned that his research did not directly evaluate the effectiveness of specific policies. To investigate, the study examined the relationship between crude birth rates and life expectancy at birth across more than 200 years of global demographic data. During this period, countries tended to follow a pattern in which fertility and life expectancy changed together while maintaining a relatively stable relationship. It is marked by low child mortality, increasing life expectancy and continued economic development, alongside falling birth rates.