Stability in the Fourth Stage: Low Births, Low Deaths in Demographic Transition

Every demographic transition story has an endpoint, and the fourth stage is where the curtain comes down on the long, dramatic gap between births and deaths. After centuries of either high mortality balancing high fertility or rapid growth fuelled by falling death rates, the fourth stage settles into a quiet equilibrium. Birth rates are low. Death rates are low. Population growth slows to a near halt. But this stability brings its own set of social, economic, and policy puzzles that countries are only beginning to solve.

What the fourth stage really looks like 🔗

The fourth stage of the demographic transition is defined by one core feature: both birth and death rates have dropped to low, roughly equal levels, and population growth approaches zero. According to Population Education, this stabilisation is enabled by strong economies, highly educated citizens, robust healthcare systems, urbanisation, and expanded employment opportunities for women. Family sizes hover around two children per couple, and childhood mortality is so low that most parents can reasonably expect every child they have to reach adulthood.

This is a profound shift from the earlier stages. In the first stage, both rates were high and roughly balanced, keeping populations small. In the second and third stages, death rates fell faster than birth rates, producing the population explosion that defined much of the 20th century. The fourth stage closes the gap again, but at a completely different scale and standard of living.

The numbers behind the stability 🔗

A total fertility rate (TFR) of about 2.1 children per woman is considered the replacement level, the point at which a population would remain broadly stable over time. Most fourth-stage countries either hover around this number or fall below it. Britannica notes that the global TFR has fallen from 5 in 1950 to 2.25 in 2024, and is projected to reach replacement level by the late 2040s. Death rates, meanwhile, are kept low by clean water, food security, immunisation, and modern medical care, with life expectancy in fourth-stage societies typically exceeding 75 years.

The medical revolution behind the long life 🔗

The fourth stage is, in many ways, a monument to medical progress. The same advances that pushed countries through the second stage, antibiotics, vaccines, sanitation, maternal care, have continued to chip away at mortality in old age. Heart disease management, cancer treatment, diabetes care, and joint replacement surgeries now routinely extend healthy life into the 70s and 80s.

This produces what demographers call a double effect on ageing. As ScienceDirect explains, when mortality is already low and continues to decline, more people reach old age, and once they get there, they live longer beyond that threshold. The result is a society with an unprecedented share of elderly citizens, including a fast-growing population of nonagenarians and centenarians.

A new kind of health profile 🔗

Long life expectancy comes with its own epidemiological signature. The diseases that dominate fourth-stage societies are no longer infectious but chronic, things like cardiovascular disease, dementia, type 2 diabetes, and cancers of ageing. A study published in Population Health Metrics on UK residents aged 80 and over found that between 1990 and 2014, nonagenarians and centenarians grew as a share of the over-80 population, while incidence of coronary heart disease and stroke fell in the 80-84 age band, even as type 2 diabetes rose sharply. The fourth stage is not just about living longer, it is about living longer with a different set of health challenges.

Countries currently in the fourth stage 🔗

The fourth stage is now home to most of the world’s wealthier economies. EBSCO Research places the United States, Canada, Australia, most of Europe, several more developed nations in Latin America, and the countries of East Asia in this group. Population Education adds Argentina, Brazil, China, Singapore, and South Korea to the list.

East Asia: the extreme end 🔗

East Asia has moved through the demographic transition faster than almost any other region in history, and the fourth-stage figures show it. According to Newsweek citing United Nations data, the 2025 projected fertility rate is around 0.73 in South Korea and Hong Kong, 0.86 in Taiwan, 1.02 in China, and 1.23 in Japan. China’s National Bureau of Statistics recorded a birth rate of 5.63 per 1,000 people in 2025, marking the fourth consecutive year with more deaths than births, while the elderly aged 60 and over now make up around 22% of the population.

Europe and North America 🔗

Europe sits at an average fertility rate of about 1.4 children per woman, and North America at around 1.6, according to Pew Research Center. The United Nations projects U.S. fertility to remain roughly stable through the end of the century, while several European countries depend on immigration to maintain a working-age population. Canada in particular relies heavily on immigration for both population growth and workforce expansion.

Where India fits in 🔗

India is not yet fully in the fourth stage, but it is moving in that direction faster than most analysts predicted a decade ago. National-level fertility has fallen close to or just below replacement, even as the population continues to grow due to the momentum built up in earlier stages. Some southern and western states have already crossed into fourth-stage territory in terms of fertility, while parts of north and central India remain in the third stage. The country offers a living textbook of demographic transition happening in real time across different regions.

Why fertility falls so far in the fourth stage 🔗

It is not just contraception that drives fertility down. Education, especially for women, transforms family planning decisions. Urbanisation raises the cost of raising children. Careers compete with parenthood. Housing, childcare, and education expenses pile up. In many fourth-stage countries, young couples are not choosing to remain childless out of disinterest in family life. As researchers cited in Newsweek’s coverage of RAND Corporation analysis noted, declining fertility often reflects unmet fertility intentions rather than a lack of desire to have children, with social and economic constraints standing in the way.

This is why pro-natal policies, cash incentives, parental leave, tax breaks, have shown such limited results. Pew Research highlights that in 2021 Japan spent 2.4% of its GDP on family benefits, and several European countries spent more than 3.0%, yet fertility rates have stayed stubbornly low. Once a society reaches the fourth stage, reversing fertility trends is far harder than slowing them.

Economic and social consequences of stability 🔗

The fourth stage is often described as the ideal demographic state, but it comes with serious adjustment costs.

An ageing workforce 🔗

With fewer young people entering the workforce and more elderly leaving it, the dependency ratio shifts. The RAND Corporation projects that China’s old-age dependency ratio, the population aged 65 and older relative to working-age people, will more than double from 0.21 in 2024 to 0.52 by 2050. Pension systems built on the assumption of a young, growing workforce face mounting strain.

Healthcare and the silver economy 🔗

Healthcare spending rises as chronic disease management dominates medical expenditure. At the same time, the elderly become a significant consumer market. China launched a national silver economy plan in 2024 aimed at services for seniors, including meal delivery, nursing homes, and tailored entertainment. Many European countries have made similar adjustments, recognising that an older population is also an economically powerful one.

Immigration as a release valve 🔗

For countries unwilling or unable to raise fertility, immigration becomes the practical solution. Canada, Australia, and Germany have leaned heavily on this strategy. Others, like Japan and South Korea, have been more cautious, leading to faster population declines and tighter labour markets.

Is there a fifth stage? 🔗

Some demographers argue that prolonged below-replacement fertility constitutes a distinct fifth stage of the transition. Population Education and other sources describe this stage as one in which deaths exceed births and natural population decline sets in, a pattern already visible in Japan, Italy, and now China. Whether this is genuinely a new stage or simply a deeper version of the fourth is still debated, but it underscores that the fourth stage is not necessarily the end of the demographic story.

The bigger picture 🔗

The fourth stage is the demographic payoff of centuries of progress in medicine, education, and economic development. It reflects societies where most people survive childhood, women have meaningful control over reproductive decisions, and life extends well into old age. Our World in Data notes that most high-income countries have reached this stage, marking a fundamental shift in human history. But the same forces that produced this stability have created new challenges, ageing populations, shrinking workforces, and policy systems built for a different demographic reality. Navigating these will define the coming decades for countries already in the fourth stage, and offer crucial lessons for those still on their way there.

What do you think? Should countries in the fourth stage focus their energy on encouraging higher birth rates, or accept low fertility and redesign their economies around an older, smaller population? And as India approaches the fourth stage in many of its regions, what lessons can it borrow from countries that got there first?

References

1. https://populationeducation.org/stage-4-demographic-transition-model/
2. https://www.britannica.com/topic/Are-Declining-Birth-Rates-a-Problem
3. https://www.sciencedirect.com/topics/social-sciences/demographic-aging
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5429583/
5. https://www.ebsco.com/research-starters/social-sciences-and-humanities/industrialization-demographic-transition-theory
6. https://www.newsweek.com/how-chinas-birth-rate-compares-world-hits-low-11381751
7. https://www.pewresearch.org/short-reads/2025/08/15/5-facts-about-global-fertility-trends/
8. https://www.rand.org/pubs/research_reports/RRA3372-1.html
9. https://populationeducation.org/what-demographic-transition-model/
10. https://ourworldindata.org/demographic-transition