Environment/Climate Change
Exposure to extreme temperatures during pregnancy and birth weight: evidence from Chile (2011 – 2020) Estela Blanco* Estela Blanco José Daniel Conejeros Paulo Guiñez María Isabel Matute Paola Rubilar Raquel Jimenez Pamela Smith
Background: Exposure to extreme temperatures during pregnancy can have adverse effects on birth weight, however, there is little evidence from Latin America.
Methods: We used birth records in 2011-2020. Mean, minimum, and maximum daily temperatures were obtained from meteorological stations in 26 municipalities representing different climatic zones of Chile. Temperature percentiles were calculated for each climatic zone and assigned for the entire pregnancy, trimester, and gestational week, using the 50th percentile for comparison. General additive models and distributed lag nonlinear models (DLNM) adjusted for month and year of last menstrual cycle and maternal and paternal: age, education, and employment.
Results: Exposure to cold mean temperatures (≤10th percentile) in the total pregnancy period and each trimester was associated with a lower mean birth weight (-28.7 gram for the total period, -45.9, -36.1, and -83.4 g for trimester 1, 2, and 3, respectively), whereas exposure to warm mean temperatures was associated with higher birth weight (21.3 g for >90th percentile). For extreme temperatures, exposure to both cold (≤10th percentile for minimum) and hot (>90th percentile for maximum) in the total pregnancy period related to lower birth weight: -48.7 g (95% CI -49.7; -47.6) and -17.48 g (95% CI -18.5; -16.4), respectively, with similar effects by trimester (Figure 1). In DLNM, consistent effects were observed later in pregnancy.
Conclusion: Lower birth weight was observed for exposure to cold temperatures and extreme heat. Exposure to warmer mean temperatures related to higher birthweight. Differing results from Chile highlight understanding regional impacts of climate change on child health.
