Q&A: Understanding impact of tiny plastics in pregnancy on fetal immune system
Key takeaways:
- Pregnant women encounter and ingest/breathe in microplastics and/or nanoplastics from various sources.
- Research is set to assess if these plastics are harmful to the placenta and fetal immune system.
The risk for allergies in children has been found to be impacted by different factors during pregnancy, including omega-3 supplementation and acid suppressant medication use.
Further, factors such as daily caffeine intake and common phenol exposure during pregnancy have been shown to impact the risk for asthma in children.
Now, researchers are studying microplastics and/or nanoplastics (MNPs) during pregnancy to uncover whether these plastic particles negatively impact the immune system of babies in the womb, according to a press release from Empa.
Notably, the release outlined that several sources — water, food and air — are ways by which individuals encounter and ingest/breathe in MNPs.
Healio spoke with Tina Bürki, PhD, scientific group leader of the Particles@barriers group at Empa, to learn more about the study, MNPs and how clinicians should advise their pregnant patients about potential risks from MNPs.
Healio: What prompted this study?
Bürki: MNPs are global contaminants of great concern for vulnerable populations such as pregnant women and the unborn child due to their biopersistence, ability to absorb pollutants (eg, pathogens, allergens) and the presence of harmful additives. MNPs taken up by the mother can be transported via the blood to the placenta and the developing fetus; however, the health consequences of MNPs in pregnancy are still largely unexplored.
Allergic diseases are among the most common chronic diseases in children and adolescents and have increased dramatically over the last 50 years. Recent studies suggest a link between allergic immune responses and in utero exposure to environmental factors including pollutant particles. Hence, we aim to investigate if MNPs could exert immunomodulatory effects at the maternal-fetal interface that could prime for the development of immune diseases in later life.
Healio: Healio previously reported that particulate matter (PM) exposure can lead to immune system dysregulation. How are PM/air pollution linked to MNPs?
Bürki: Microplastics (< 5 mm) and nanoplastics (< 1 µm) are a sub-fraction of PM, a major component of air pollution. Airborne MNPs contribute to PM10 and PM2.5, which refer to particulate matter with diameters below 10 µm and below 2.5 µm, respectively.
Healio: Do you have any hypotheses for how the presence of these plastics can trigger or worsen asthma, allergy and other immunologic diseases?
Bürki: It is possible that MNPs could have direct immunomodulatory properties similar to few other nanoparticles, which have shown immune-activating and suppressing activities. Alternatively, plastic particles could absorb allergens from the environment and transport them as carriers to the placenta and/or the unborn child as described for other nanoparticle-allergen complexes (eg, diesel exhaust particle-grass pollen allergen complexes, which could induce the production of allergen-specific IgE).
Healio: Why is finding out the impact of MNPs specifically in pregnant women and children important? Do you have any hypotheses for how these plastics can be the cause of asthma, allergies and other immunologic diseases in the children of women exposed to them?
Bürki: The immunology of pregnancy is highly complex and involves a series of immunological changes that are actively coordinated and carefully controlled to prevent rejection of the “foreign” fetus while allowing implantation, formation of the placenta and development of the fetus. The placenta, along with the maternal immune system, plays a central role in providing the signals necessary to control the immune response at the maternal-fetal interface. Therefore, it is conceivable that chronic diseases, including allergies, could have an origin in the placenta.
In our previous studies, we have observed a size-dependent placental passage of polystyrene MNPs with higher fetal transfer for smaller particles. Translocated MNP particles could directly interact with fetal immune cells to affect the development of the immune system. In addition, larger MNPs that accumulate but do not cross the placental barrier could interfere with the secretion of essential immunomodulatory, inflammatory and endocrine mediators important to shape the fetal immune system.
Recently, we have observed evidence for such indirect placenta-mediated fetotoxicity for other nanoparticles including diesel exhaust particles. Hence, we would like to understand if MNPs could alter fetal immune programming by similar mechanisms.
Healio: How will you be assessing MNPs in pregnant women and children? What are your study endpoints?
Bürki: We will study the placental uptake and translocation of different industrial and environmentally relevant MNPs as well as their impact on placental and fetal immune cells with a focus on immune/inflammatory responses. To achieve human relevant results, we will use human-based placenta models including placental explant cultures, ex vivo perfusion models and microphysiological chip.
Healio: What do you hope to uncover/determine in this research?
Bürki: We aim to achieve a better understanding of the potential health risks of MNP in pregnancy to provide novel insights essential for the sustainable production and use of plastics, the protection of pregnant women and unborn children, and the prevention of chronic diseases (eg, allergies) later in life.
Healio: How should clinicians advise their pregnant patients about potential risks from MNPs?
Bürki: As a precautionary measure to reduce MNP exposure and minimize potential health effects until we have a better understanding of the health impacts MNPs have on pregnancy, conceiving mothers could be advised to avoid heating food in plastic containers (heating is inducing a higher release of microplastics), to eat fresh foods (processed foods often contain microplastic contamination) and to regularly ventilate and dust indoor rooms (household dust often has a higher concentrations of airborne microplastics, eg, from synthetic textiles).
References:
- Dugershaw-Kurzer B, et al. Adv Sci (Weinh). 2024;doi:10.1002/advs.202401060.
- How dangerous are nanoplastics for babies in the womb? https://www.empa.ch/web/s604/nanoplastik-in-der-schwangerschaft-als-risiko-fuer-allergie-entwicklung. Published Feb. 5, 2025. Accessed Feb. 5, 2025.
- Wick P, et al. Environ Health Perspect. 2009;doi:10.1289/ehp.0901200.
For more information:
Tina Bürki, PhD, can be reached at tina.buerki@empa.ch.