Population Growth Concentrated Among the Poorest Communities

As sub-Saharan African countries strive to grow their economies, it is critical that they consider their age structures—or more particularly, the age structures of their richest and poorest populations, which are determined largely by fertility rates. Comparing these can unmask an imbalance that, if corrected, could accelerate economic growth and help break the cycle of poverty.

This assessment could be imperative for sub-Saharan Africa, where the population of poor countries continues to grow rapidly. A September commentary by Bill and Melinda Gates in The New York Times explains that births are increasingly concentrated in places where poverty is high. “Based on current trends, a growing proportion of babies will be born in places where adults have to devote most of their resources to survival, leaving very little to invest in their families, their communities and their countries,” they wrote.

Consider the disparity in Tanzania: Women in the richest one-fifth of the population have about three children during their lifetimes, while women in the poorest one-fifth have an average of between seven and eight children. A key driver of this is more contraceptive use among the wealthy. A 2015 study of data from 46 developing countries found that on average 51 percent of the richest population quintile used contraception compared with 32 percent among the poorest quintile.1

The differences in contraceptive use between the richest and poorest women reflect the number of children they want and their ability to avoid unintended pregnancies by knowing about and being able to access and afford modern contraceptives.

As fertility declines and fewer babies are born, a youthful population transitions to a structure where people of working age greatly outnumber young dependents. If enough jobs are available, household income increases, and households with fewer children can afford to make larger investments in child health and education and to build up their savings. This demographic shift needs to occur among both the rich and the poor for a country to achieve accelerated as well as inclusive economic growth.

A Population Reference Bureau policy brief (April 2018) examined these two wealth-based disparities in four sub-Saharan African countries (Ethiopia, Ghana, Malawi, and Tanzania) by looking at rates of modern contraceptive use and demand for modern methods satisfied. Women who want to delay or prevent pregnancy and who are using modern contraception are considered to have their demand satisfied.

Among the four countries, Malawi stands out for having the largest increase in modern contraceptive use and the smallest gap in use between rich and poor. Among the richest quintile, 61 percent of married women use modern contraception, as do 53 percent of the women in the poorest quintile. Though fertility decline has been slower than expected with such high contraceptive use, it has been falling among both the richest and poorest subgroups.

If Malawi can sustain its fertility decline, its richest quintile is projected to reach a replacement level fertility rate of 2.1 by 2032, and the poorest quintile by 2035. By 2050, the proportion of children will shrink and the majority of both quintiles will comprise working-age adults.

Malawi’s success stems from early efforts to use data to make strategic decisions. These included community-focused initiatives to provide services to rural women, since 85 percent of the country’s population is rural, according to the brief. Among these initiatives was a task-shifting strategy that allowed nurses to provide long-acting contraceptive methods and community-based health workers to administer injectable contraceptives, the modern method preferred by Malawian women. The government also used mass media to increase knowledge of family planning, which has served to increase contraceptive demand overall but especially among the poor.

Tanzania, by contrast, has seen its fertility rate fall very slowly over the last two decades among the richest quintile, from about four children per woman to three in 2015, and stagnate at between seven and eight children in the poorest quintile. Here, the gap between rich and poor is large, a situation unlikely to be helped by Tanzanian President John Magufuli’s recent advice that women abandon contraception and have more children.

Use of modern contraceptives in Tanzania has increased among both quintiles since 1995, but it is still low at 35 percent among the wealthy and 20 percent among the poorest. If these rates continue, by 2050, more than half of the poorest population will still be under age 15. However, increases in contraceptive use overall, especially among the poorest women, would yield more inclusive growth with economic benefits at both the household and national levels.

To accelerate contraceptive use among its poorest women, Tanzania could improve access to family planning in rural areas by incorporating community health workers into the formal health system with permanent funding, the brief says. Task-shifting could also extend the reach of longer acting contraceptives, such as implants and intrauterine devices, to underserved populations.

Tanzania and other sub-Saharan African countries with large wealth-based disparities in contraceptive use can take a page from Malawi’s success that coupled strong political commitment with use of data to make strategic decisions that help to foster inclusive growth and shared prosperity.

PRB’s 2016 report Fostering Economic Growth, Equity, and Resilience in Sub-Saharan Africa: The Role of Family Planning includes a similar analysis for Kenya, Nigeria, Rwanda, and Uganda.


  1. John Ross, “Improved Reproductive Health Equity Between the Poor and the Rich: An Analysis of Trends in 46 Low- and Middle-Income Countries,” Global Health: Science and Practice 3, no. 3 (2015): 419-45