View All Articles
  • 04 December 2019
  • 3 min read

Hot temperatures could be linked to early birth

Subscribe To Advice

Shorter gestational periods have been linked to negative health and cognitive outcomes later in life.

Study links hot temperatures to early birth

Hot temperatures could be linked to early birth, scientists say.

A study found a spike in birth rates when temperatures reach 32.2C when researchers looked at birth records of 56 million Americans born between 1969 and 1988.

During this period, an average of 25,000 babies were born up to two weeks early each year as a result of heatwaves, according to the study.

This represents a loss of more than 150,000 gestational days annually, according to scientists from the University of California Los Angeles (UCLA).

Shorter gestational periods have been linked to negative health and cognitive outcomes later in life.

Previous research has linked hot weather to an acceleration of childbirth and shorter gestations.

Search Jobs

1000s of jobs for Nurses & Care Professionals. No.1 for UK nursing, care & healthcare jobs.

Search Jobs

Study covered 56 million births in US

Scientists used estimated changes in daily birth rates from counties across America to quantify the total number of lost days of gestation associated with heat over a span of two decades.

The sample for the research published in Nature Climate Change (NCC) included 56 million births.

Researchers estimate that birth rates increase by five% on days with a maximum temperature above 32.2°C (90°F), with an average gestational reduction of 6.1 days – some births occurred two weeks early.

The authors, Dr Alan Barreca from UCLA, and Dr Jessamyn Schaller of the National Bureau of Economic Research, in Massachusetts, write: “We find that extreme heat causes an increase in deliveries on the day of exposure and on the following day and show that the additional births were accelerated by up to two weeks.”

They add: “While we posit climate change will cause gestational losses, the exact magnitude of the future costs is highly uncertain – households may adapt as expectations about the frequency of hot weather events increase, which could mitigate impacts on infant health.

“Indeed, we find that access to air conditioning is an effective adaptation strategy and one that is likely to be adopted more in places where hot weather is currently infrequent.”

Findings do not take into account why women deliver in the US

Andrew Shennan, professor of obstetrics, King’s College London, said: “The findings are valid and well researched, but they do not take into account why women deliver.

“As a large proportion of births, especially in the USA are precipitated by doctors – inductions or Caesareans, there may be social reasons – eg: women requesting delivery earlier when they are uncomfortable with the heat.

“This requires further evaluation to understand mechanisms. “Extremes of temperatures, both hot and cold have previously been linked to risk of both stillbirth and delivery. Mechanisms are not clear.

“Given the wide variety of temperatures around the world, and that most women have normal pregnancies, this is unlikely to be an important risk factor for any individual.”

What Do You Think?

Ask questions, comment and like this article below! Share your thoughts, add your opinion in the comments below.


Related stories

Babies and mothers died amid toxic culture at NHS trust

Top 10 royal birth facts

Sperm frozen long-term makes no difference to birth rates

Do men make good midwives?

Like this article? Get The Nurses Weekly!

About the author

  • Nurses news editorial team

Bringing you a daily update of nursing, NHS, health and social care news from around the UK. Advice

Subscribe to receive advice, insights and inspiration to help you progress your career.


Care Professionals Helping One Another is a community where people like you can contribute and share advice. Learn & never miss out on updates. Subscribe to be part of our community.