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Meta-Analysis
. 2023 Feb 1:318:120850.
doi: 10.1016/j.envpol.2022.120850. Epub 2022 Dec 14.

A systematic review of evidence for maternal preconception exposure to outdoor air pollution on Children's health

Natalie Blanc  1 , Jiawen Liao  2 , Frank Gilliland  2 , Junfeng Jim Zhang  3 , Kiros Berhane  4 , Guoying Huang  5 , Weili Yan  5 , Zhanghua Chen  6
Affiliations
Meta-Analysis

A systematic review of evidence for maternal preconception exposure to outdoor air pollution on Children's health

Natalie Blanc et al. Environ Pollut. .

Abstract

The preconception period is a critical window for gametogenesis, therefore preconception exposure to air pollutants may have long-term effects on children. We systematically reviewed epidemiological evidence concerning the effects of preconception ambient air pollution exposure on children's health outcomes and identified research gaps for future investigations. We searched PubMed and Web of Science from journal inception up to October 2022 based on an established protocol (PROSPERO: CRD42022277608). We then identified 162 articles based on searching strategy, 22 of which met the inclusion criteria. Studies covered a wide range of health outcomes including birth defects, preterm birth, birthweight, respiratory outcomes, and developmental outcomes. Findings suggested that exposure to outdoor air pollutants during maternal preconception period were associated with various health outcomes, of which birth defects has the most consistent findings. A meta-analysis revealed that during 3-month preconception period, a 10 μg/m3 increase in PM10 and PM2.5 was associated with relative risk (RR) of birth defects of 1.06 (95% confidence interval (CI): 1.00, 1.02) and 1.14 (95% CI: 0.82, 1.59), respectively. Preterm birth, low birthweight, and autism have also been associated with maternal preconception exposure to PM2.5, PM10, O3 and SO2. However, the significance of associations and effect sizes varied substantially across studies, partly due to the heterogeneity in exposure and outcome assessments. Future studies should use more accurate exposure assessment methods to obtain individual-level exposures with high temporal resolution. This will allow the exploration of which specific time window (weeks or months) during the preconception period has the strongest effect. In future epidemiologic studies, integrating pathophysiologic biomarkers relevant to clinical outcomes may help improve the causal inference of associations between preconception exposure and health outcomes suggested by the current limited literature. Additionally, potential effects of paternal preconception exposure need to be studied.

Keywords: Air pollution; Birth defects; Birthweight; Preconception; Preterm birth.

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Conflict of interest statement

Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Figure 1.
Figure 1.
Flowchart Showing the Study Selection and Screening Processing.
Figure 2.
Figure 2.
Forest Plot Showing the Associations of Preconception Air Pollution Exposure with Birth Defect per 10 μg/m3 (for PM2.5 and PM10) or 10 ppb (for NO2, SO2, and O3) or 100 ppb (for CO) increase in 3-month Preconception Average Concentration. (ES: effect size; CI: confidence interval). *Indicating converted effect size from the original article
Figure 3.
Figure 3.
Forest Plot Showing the Associations of Preconception Air Pollution Exposure with Preterm Birth per 10 μg/m3 (for PM2.5 and PM10) or 10 ppb (for NO2, SO2, and O3) or 100 ppb (for CO) increase in 3-month Preconception Average Concentration. (ES: effect size; CI: confidence interval). *Indicating converted effect size from the original article
Figure 4.
Figure 4.
Forest Plot Showing the Associations of Preconception Air Pollution Exposure with Small for Gestational Age per 10 μg/m3 (for PM2.5 and PM10) or 10 ppb (for NO2, SO2, and O3) or 100 ppb (for CO) increase in 3-month Preconception Average Concentration. (ES: effect size; CI: confidence interval). *Indicating converted effect size from the original article
Figure 5.
Figure 5.
Forest Plot Showing the Associations of Preconception Air Pollution Exposure with Autism Spectrum Disorder per 10 μg/m3 (for PM2.5 and PM10) or 10 ppb (for NO2, SO2, and O3) increase during 3-month Preconception Period. (ES: effect size; CI: confidence interval). *Indicating converted effect size from the original article
See this image and copyright information in PMC

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