# Biological signatures of prenatal wildfire smoke exposure and fetal and infant growth

> **NIH ES R21** · WASHINGTON UNIVERSITY · 2025 · $427,625

## Abstract

Wildfires are occurring across the US and globally with potentially harmful impacts on
maternal and child health. Although research into health effects specific to wildfire smoke
exposure in pregnancy is nascent, a recent meta-analysis on more than 1.7 million births
showed that maternal exposure during late pregnancy was linked to reduced birth weight
and preterm birth. However, the short and long-term effects of repeated wildfire smoke
exposure during pregnancy on maternal and fetal health outcomes have not been
investigated in depth, nor are any molecular mechanisms responsible for such effects well
understood. Therefore, there is an urgent need to understand the how wildfire smoke
exposure affects health and wellbeing. One hypothesized mechanism to facilitate
biological communication from pollutants inhaled in the lung to distal organs and tissues
is through extracellular vesicles (EVs). EVs contain a variety of biologically active
molecules including microRNAs (miRNAs) which are small ~22 nucleotide-long noncoding
RNA molecules. EV-miRNA might be the ideal candidates to mediate effects of wildfire
smoke exposures on pregnancy because they can be produced by the respiratory system
where the initial exposure occurs and then enter the circulation to affect distant tissues
and organs. We hypothesize that prenatal exposure to wildfire smoke triggers a biological
response that can be measured in EV-miRNA, and that these wildfire smoke-related
biological signatures are negatively associated with fetal and infant growth. We will
additionally investigate the interplay between smoke exposure and miRNA signatures with
neighborhood characteristics, including housing, infrastructure, and other factors that may
modify effects on fetal and infant growth. We will examine this hypothesis in 466
participants in MADRES—a cohort representative of the population living in Los Angeles,
CA – in the following aims: Aim 1) Identify unique EV-miRNA transcriptomic signatures of
wildfire 

## Key facts

- **NIH application ID:** 11468601
- **Project number:** 7R21ES036649-02
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Carrie Van Doren Breton; Rima  Habre
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** ES
- **Fiscal year:** 2025
- **Award amount:** $427,625
- **Award type:** 7
- **Project period:** 2026-04-24T00:00:00 → 2027-09-18T00:00:00

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11468601

## Citation

> US National Institutes of Health, RePORTER application 11468601, Biological signatures of prenatal wildfire smoke exposure and fetal and infant growth (7R21ES036649-02). Retrieved via AI Analytics 2026-06-25 from https://api.ai-analytics.org/grant/nih/11468601. Licensed CC0.

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