Extreme heat risks to pregnancy driven by climate change: Brazil

2020 to 2024

We counted the number of days with temperatures warmer than 95% of temperatures observed at a given location (also referred to as temperatures above the 95th percentile) — a threshold which research1 shows can bring increased risk of preterm birth. We define these extremely hot days as “pregnancy heat-risk days.”

  • During the past five years, Brazil experienced an average of 27 additional pregnancy heat-risk days each year.

  • Climate change accounted for three-quarters of the average annual pregnancy heat-risk days in Brazil during 2020 to 2024 (27 of 36 days).

  • The city of São Luís, Maranhão experienced the most additional pregnancy heat-risk days each year (49) in Brazil on average during the past five years.

  • In Macapá (the capital of the Amapá state), nearly all of the pregnancy heat-risk days experienced annually in the past five years were added by climate change (35 out of 36 days). Meaning, this city would have experienced only one pregnancy heat-risk day each year, on average, without the influence of climate change.

Explore data for states and cities across Brazil in the interactive maps below.


States with the most pregnancy heat-risk days added by climate change




Cities with the most pregnancy heat-risk days added by climate change



1We chose this percentile based on peer-reviewed research from Kuehn et al. (2017), Wang et al. (2013), Wang et al. (2024), and McElroy et al. (2022).