Baby boom and baby bust seen in latest world fertility rates

Published 29 November 2018

Global fertility rates have declined substantially since 1950. Currently in many nations, fertility rates are not high enough to maintain current population levels, but in others, largely in sub-Saharan Africa, high fertility rates are still driving population increases.

Global population has been increasing by an average of 83.8 million people per year since 1985

Among its many findings, this complex study found that, despite an overall fall of 49.4% in total fertility rate (from 4.7 live births to 2.4), global population has been increasing by an average of 83.8 million people per year since 1985, and in 2017 was put at 7.6 billion (up from an estimate of 2.6 billion in 1950). However, at the national level total fertility rate did decline in all countries between 1950 and 2017; in 2017 rates ranged from a low of 1.0 live births in Cyprus to a high of 7.1 live births in Niger.

However, the authors note that 'total fertility rate' masks variation in trends in fertility at different ages and in different countries. Thus, age-specific fertility rate in women up to the age of 25 was lower than that in women of an older age. Similarly, of the 59 countries with a total fertility rate of more than three live births per woman in 2017, 41 were in sub-Saharan Africa. Of the remainder, six countries were in north Africa and the Middle East.

By contrast, the study found that 33 countries have been in overall population decline since 2010, including Estonia, Ukraine, Belarus, Greece, Georgia, Bulgaria, Romania, and Spain. Many other countries, say the authors, are also likely to have decreasing populations as the size of their birth cohorts reduces. Population decline and the associated shift to an older population has profound cultural, economic, and social implications, they note.

And, while the study offers no detailed explanation for the decline in fertility rate, the authors do note that options to deal with the social and economic consequences of population decline include pro-natalist policies (which in a few countries have included state-funded IVF), liberal immigration policies, and increasing the retirement age.

1. GBD 2017 Population and Fertility Collaborators. Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017. Lancet 2018; 392: 1995–2051.

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