1. Death rates and birth rates are high and are roughly in balance.
2. Death rates drop rapidly due to improvements in food supply and sanitation, which increases life spans and reduces diseases. Without a corresponding fall in birth rates, the countries in this stage experience a large increase in population.
3. Birth rates fall due to access to contraception, increases in wages, urbanization, an increase in the status and education of women, and other social changes. Population growth begins to level off.
4. Birth rates and death rates are both low. Birth rates may drop below replacement level, leading to a shrinking population. Death rates may remain consistently low or increase slightly due to increases in lifestyle diseases due to low exercise levels and high obesity.