Higher ambient temperature and the risk of poor outcomes in pregnancy
Citation: Chersich MF, Pham MD, Areal A, et al. Associations between high temperatures in pregnancy and risk of preterm birth, low birth weight, and stillbirths: systematic review and meta-analysis. BMJ. 2020;371:m3811.
What is this? Climate change is leading to increases in ambient temperature. There are concerns that exposure to high ambient temperatures in pregnancy might increase the risk of preterm birth, low birth weight and stillbirths.
In this systematic review, the authors searched for studies on the effects of exposure to high ambient temperatures during pregnancy. They restricted their searches to articles published in Chinese, English, German and Italian and did the most recent search in September 2019. They included 70 studies, from 7 low- or middle-income countries and 20 high-income countries.
What was found: Exposure to high ambient temperatures increases the likelihood of stillbirth and pre-term birth.
The risks of high ambient temperatures for pregnancy outcomes might be largest in low- and middle-income countries.
The effects of high ambient temperatures on the risk of low birth weight are uncertain, with considerable heterogeneity in the results of the 28 studies that reported on this.