The number of births in the USA in 2024 increased by only one percent since the previous year, the Centres for Disease Control and Prevention (CDC) reports.

The CDC examined more than 99 percent of the national records of births that occurred in 2024, which included information about the age of the mothers. The general fertility rate, indicating the number of births per 1000 women aged between 15 and 44, was 54.6. This was an increase of less than one percent from a record low of 54.5 in 2023. The slight increase in birth rate was driven by women above 25 years old, while younger women and teenagers had fewer children than in 2023.

Dr Brady Hamilton, a statistician at the CDC, and first author of the report, explained that this result is 'a continuation of the general downward trend in births to teenagers and upward trend in births to older women seen for the last three or so decades.' He added that the CDC could not speculate about what is causing this pattern.

The figures fit into a context of progressive decline in population size in which the number of births decreased by an average of two percent per year from 2015 to 2020, and fluctuated 2021-2024. The total fertility rate, which estimates the number of births a hypothetical group of 1000 women would have over their lifetime, was 1626.5 in 2024. This is a less than one percent increase since 2023, and below the rate necessary to maintain the population size, generation to generation (called the replacement level), estimated at 2100 births per 1000 women. The total fertility rate has been continuously below the replacement level since 2007, but a negative trend was already present since 1971.

Similar trends have been noted worldwide, including in the UK (see BioNews 1263). Sociologists have suggested several economic and social factors which may be influencing people's decisions about whether and when to have children, and contributing to declining birth rates.

'It's not that people are deciding against having kids at all,' Professor Karen Guzzo, director of the Carolina Population Centre at the University of North Carolina at Chapel Hill, who was not involved in the report, told NBC News. Rather, she said, people are pondering on questions like: 'Do I have the right partner? If I have another baby in child care, what would that do to my expenses? Does my job feel stable?'

In addition, Professor Guzzo told the New York Times that factors like unfavourable economic conditions, lack of paid parental leave and the difficulty in buying a house might be inducing American couples to renounce or postpone having children: 'People don't have kids when they don't feel good about their own futures.'

The report also showed that birth rates among teenagers have consistently decreased by four percent per year since 2007, which was welcomed by some as a positive trend. Professor Guzzo told NBC: 'It's good news when people can avoid having kids at periods of their life where they themselves would say "This is not the right time".'