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Micro and Nanoplastics and Obstetric Outcomes in Humans and Animals: A Systematic Review

International Journal of Environmental Research and Public Health 2026
Blanca Novillo-Del Álamo, Alicia Martínez-Varea, Imelda Ontoria-Oviedo, Alba Ruiz-Gaitán, Charlotte Cosemans, Michelle Plusquin, Beatriz Marcos-Puig

Summary

This review pulled together 12 studies (in humans and mice) looking at tiny plastic particles—called micro- and nanoplastics—that have been found in the placenta, and found early hints that they may be linked to premature birth, low birth weight, poor fetal growth, and miscarriage. That said, the research is still limited and inconsistent, so scientists can't yet say plastics *cause* these problems—but it's a good reason to keep an eye on this emerging area as we learn more about how plastic pollution might affect pregnancy.

Polymers
Study Type Review

Background: Micro- and nano-plastics (MNPs) are pervasive environmental contaminants that accumulate in various tissues, including the placenta. Experimental and clinical studies suggest potential cytotoxic, oxidative, and inflammatory effects that may lead to placental dysfunction and adverse obstetric outcomes. However, high-quality evidence on the clinical relevance of MNPs exposure during pregnancy remains scarce, underscoring the need for systematic evaluation of their impact on maternal and fetal health. Methods: The databases PubMed, ScienceDirect, CENTRAL, Embase, MDPI and Google Scholar were searched for studies published up to September 2025 investigating the relationship between MNPs and obstetric outcomes. Results: Twelve studies were included in this review, with half employing an observational design in human subjects and the other half using experimental studies in murine models. Although the available evidence is limited, there are studies reporting the association between MNPs exposure and premature birth, low birth weight, intrauterine growth restriction, and miscarriage. The most prevalent polymer detected was polyethylene, and the most commonly used MNPs detection techniques were Raman microspectroscopy, digital microscopy, Fourier Transform Infrared, and Pyrolysis gas chromatography-mass spectrometry. Conclusions: This systematic review summarizes current limited insights on the potential effects of MNPs on obstetric outcomes, highlighting possible associations with low gestational age, low birth weight, intrauterine growth restriction, and miscarriage. Findings do not allow causal inference due to heterogeneity in study design, exposure assessment, contamination control, and analytical methodologies.

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