Climate change and pre-term delivery

Me, holding my daughter

As we all know, climate change is caused mostly by human. We live in a period called anthropocene. This term indicated the fact that humans have an impact on Earth’s geology and ecosystem.

Just to have an idea of human impact, take just threes minutes to look at this video:

A recent study published on Nature Climate Change by Barreca and collaborators (from UCLA) suggests that climate change has also an impact on the date of delivery.

Human pregnancy last in average 40 weeks. Children born at 37 weeks or before are considered to be premature. But also deliveries between 37 and 40 weeks are not ideal.

Researchers analyzed daily temperatures and birth rated in the U.S.A. from 1969 and 1988.

They discovered that the days when temperatures reached 32 °C, the birth rate increased by 0.97 every 100,000 women.

The motivations why heat increases deliveries is not entire clear. One possibility is that heat increases cardiovascular stress, which induces labor. Another theory suggests that heat increases the level of oxytocin, the hormone responsible for labor induction and lactation. A third theory involves loss of sleep. Heat has an impact on the possibility for a pregnant woman to sleep well, and therefore could have a role in labor.

In average, researchers calculated that an early birth at 32° C corresponds at 6.1 days of less gestation time.

Since 1988, climate change is getting worse, therefore more babies are expected to come to this world too early. Climate change projections suggest losses of 250,000 days of gestation per year by the end of the century.


Barreca et al., “The impact of high ambient temperatures on delivery timing and gestational lengths”, Nature Climate Changes, (2019) doi:10.1038/s41558-019-0632-4

Info on climate change:


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