According to a new study published in the Proceedings of the National Academy of Sciences (PNAS), increases in life expectancy in highly developed countries have slowed since 1939.

While life expectancy previously increased by 5.5 months with each new generation, for people born between 1939 and 2000, this figure has dropped to 2.5–3.5 months per generation.

Projections indicate that no generation born after 1939 is expected to reach an average life expectancy of 100 years.

The main reason for the slowdown is the reduction in infant mortality, which previously contributed significantly to gains in life expectancy. Improvements in older age groups are now insufficient to compensate for slower gains in infancy. As a result, even with better adult survival, life expectancy will not grow at the same pace as in the first half of the 20th century.

The study emphasizes the importance of accounting for these trends in planning pension systems, healthcare, and social policies.

Without major medical breakthroughs in the near future, life expectancy in highly developed countries is unlikely to return to the growth rates observed in the early 20th century.

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