Association of Air Pollution and Heat Exposure on adverse pregnancy outcomes
This JAMA Network Open article performed a systematic review of 57 studies with air pollution and heat on birth outcomes.
They found looks that exposure to ozone and PM 2.5 was associated with preterm birth and low birth rates, highest in communities of color and those with asthma.
IMPORTANCE Knowledgeofwhetherseriousadversepregnancyoutcomesareassociatedwith increasingly widespread effects of climate change in the US would be crucial for the obstetrical medical community and for women and families across the country.
OBJECTIVE Toinvestigateprenatalexposuretofineparticulatematter(PM2.5),ozone,andheat, and the association of these factors with preterm birth, low birth weight, and stillbirth.
EVIDENCEREVIEW Thissystematicreviewinvolvedacomprehensivesearchforprimaryliterature in Cochrane Library, Cochrane Collaboration Registry of Controlled Trials, PubMed, ClinicalTrials.gov website, and MEDLINE. Qualifying primary research studies included human participants in US populations that were published in English between January 1, 2007, and April 30, 2019. Included articles analyzed the associations between air pollutants or heat and obstetrical outcomes. Comparative observational cohort studies and cross-sectional studies with comparators were included, without minimum sample size. Additional articles found through reference review were also considered. Articles analyzing other obstetrical outcomes, non-US populations, and reviews were excluded. Two reviewers independently determined study eligibility. The Arskey and O’Malley scoping review framework was used. Data extraction was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.
FINDINGS Ofthe1851articlesidentified,68mettheinclusioncriteria.Overall,32798152births were analyzed, with a mean (SD) of 565 485 (783 278) births per study. A total of 57 studies (48 of 58 [84%] on air pollutants; 9 of 10 [90%] on heat) showed a significant association of air pollutant and heat exposure with birth outcomes. Positive associations were found across all US geographic regions. Exposure to PM2.5 or ozone was associated with increased risk of preterm birth in 19 of 24 studies (79%) and low birth weight in 25 of 29 studies (86%). The subpopulations at highest risk were persons with asthma and minority groups, especially black mothers. Accurate comparisons of risk were limited by differences in study design, exposure measurement, population demographics, and seasonality.
CONCLUSIONSANDRELEVANCE Thisreviewsuggeststhatincreasinglycommonenvironmental exposures exacerbated by climate change are significantly associated with serious adverse pregnancy outcomes across the US.