Patterns of fertility decline in developing countries, 1950-75

Area of Science:

• Demography
• Sociology
• Global Health

Background:

• Crude birth rates (CBRs) in developing countries averaged 42 per thousand annually in 1950.
• Initial declines in CBRs post-1950 were observed in limited, smaller nations.
• Substantial global population shifts necessitate understanding fertility rate dynamics.

Purpose of the Study:

• To analyze trends in crude birth rates across developing countries from 1950 to 1975.
• To identify sociodemographic factors contributing to observed fertility declines.
• To assess the impact of these factors on population dynamics in large developing nations.

Main Methods:

• Analysis of population figures and vital statistics over a 25-year period (approx. 1950-1975).
• Examination of crude birth rate data, acknowledging potential data deficiencies.
• Statistical review of sociodemographic variables influencing fertility.

Main Results:

• Significant declines in crude birth rates observed in many developing countries after 1965.
• For 13 large developing countries (over 35 million population), average CBR decline was 13% post-1965.
• Nine of these large countries experienced CBR declines exceeding 12%.

Conclusions:

• Increases in the age at first marriage were a primary factor in reducing birth rates.
• Decreases in marital fertility rates also significantly contributed to the observed declines.
• These trends indicate a notable demographic transition in developing regions.