Reproductive toxicity of micro- and nanoplastics: Insights from experimental and human studies.
Level 5 - mechanism / opinion, no new human data
Scoping review summarizing in vitro, animal, and descriptive human biomonitoring studies
PubMed 41164869 · doi:10.1111/joim.70038
What was done
A scoping review of 40 original studies published over the last decade evaluating the reproductive hazards of micro- and nanoplastic (MNP) exposure. The authors synthesized findings from in vitro experiments, 30 in vivo animal studies, and human biomonitoring/epidemiological data regarding particle distribution and cellular pathways.
What was found
Humans are estimated to absorb 74,000–121,000 MNP particles annually. MNPs were documented in human breast milk, placenta, endometrium, ovaries, testis, semen, follicular fluid, blood, and urine. In 30 animal studies, MNP exposure was linked to altered semen quality and spermatogenesis in males, and disrupted folliculogenesis, depleted ovarian reserve, and reduced litter sizes in females, along with possible transgenerational effects. Identified cellular mechanisms included disruption of steroidogenesis, energy metabolism, inflammation, and oxidative stress. Quantitative effect estimates for human fertility outcomes were not provided in the abstract.
Why it matters
This review maps the biological presence of plastic particles in reproductive organs and links experimental mechanisms to potential causes of declining global fertility.
Limits
The available evidence relies heavily on animal models and in vitro testing rather than direct human clinical reproductive trials. The abstract notes that disentangling the toxicity of physical plastic particles from their chemical additives remains challenging, and specific human exposure thresholds or quantitative clinical risk ratios are not established.
Cited by
- supports Microplastics have been detected and measured in human blood, placentas, seminal fluid, and breast milk.