Keeping babies alive will lower population growth

23 02 2023

We’ve just published a paper in PLOS ONE showing high infant mortality rates are contributing to an incessant rise of the global human population, which supports arguments for greater access to contraception and family planning in low- and middle-income nations.

In collaboration with Melinda Judge, Chitra Saraswati, Claire Perry, Jane Heyworth, and Peter Le Souëf of the University of Western Australia‘s School of Medicine and the Telethon Kids Institute, we found that higher baby death rates and larger household sizes (as an indicator of population density) lead to higher fertility rates.

In the first study of its kind, we provide a compelling argument that the United NationsSustainable Development Goals for reducing infant mortality can be accelerated by increasing access to family planning.

Although it sounds counterintuitive, higher baby death rates are linked to higher population growth because the more babies a women loses, the more children she is likely to have. Family planning, including access to quality contraception, enables women to plan pregnancies better and therefore reduce infant mortality to curb the so-called ‘replacement’, or ‘insurance’ effect.

We evaluated six conditions thought to influence a woman’s fertility — availability of family planning, quality of family planning, education, religion, mortality, and socio-economic conditions, across 64 low- to middle-income countries.

Specifically, we tested whether

  • increasing the availability of family planning is associated with reduced fertility;
  • increasing the quality of family-planning services is associated with reduced fertility;
  • increasing years of female education is associated with reducing fertility;
  • increased fertility is observed in countries with a higher prevalence of adherents of Catholicism or Islam, two main religions that expressly dictate elements of fertility and/or family structure;
  • a larger mean household size is positively correlated with fertility, and lower socio-economic conditions; and
  • higher mortality (both infant and maternal) is associated with higher fertility.

Keeping babies alive actually reduced average fertility and helps put the brakes on population growth. Essentially, higher infant mortality and a larger household size increased fertility, whereas greater access to any form of contraception decreased fertility.

Interestingly, female education, home visits by health workers, quality of family planning services, and religious adherence all had weak, if any, contribution at the scale of entire countries.

The United Nation’s Sustainable Development Goals 3 (good health and wellbeing) and 5 (gender equality) emphasise the basic right to exercise control over sexual and reproductive health through universal access to family planning.

The world is not on track to meet Goal 3 to reduce global maternal mortality to less than 70 per 100,000 live births and end preventable deaths of newborns and children under 5 years of age by 2030. Our results show the best pathway toward reaching these targets is by providing readily available and high-quality family-planning services. These actions will not only to decrease fertility rates, they will also to lower the number of unintended pregnancies, infant deaths, and maternal deaths.

Our findings support the notion that to encourage continued declines in global fertility, both infant survival rates plus access to contraception need to be increased.

Recommendations for measures to decrease infant mortality emphasise improving the quality of antenatal care, increasing the number of trained healthcare staff at births, and improving postnatal care for both infants and mothers. Given the evidence that large households can worsen child health, improving living conditions to ameliorate high-density living could also indirectly result in lower fertility.

Allowing parents to choose family planning by providing readily available, modern methods of contraception can be expected to improve infant survival as well as reduce maternal mortality. This is because parents can plan and space their births, and being able to decide to have fewer children also has the potential to facilitate better investment in the overall health and well-being of families. It emphasises the importance of providing access to contraception as a direct contribution to decreasing infant mortality.

If we don’t act now to achieve the UN’s Sustainable Development Goals, fertility will rise, more children will die, and more women will succumb to birth-related deaths.

CJA Bradshaw



One response

23 02 2023

Note that PLoS One has ignored repeated attempts to correct the title online and in the PDF version.

The title should be:

“Lower infant mortality, lower household size, and more access to contraception reduce fertility in low- and middle-income nations”


“Lower infant mortality, higher household size …”

Not happy.


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