A review of the impact of micro- and nanoplastics on female reproduction: What we know and gaps in knowledge.

Micro-and nanoplastics (MNPs) are breakdown products of plastics, and humans are exposed to these particles through air, water, food, and soil. There is a growing concern that human exposure to MNPs negatively impacts health. In this review we will discuss the potential health impact of MNPs on ovarian function and the hypothalamic-pituitary-ovarian (HPO) axis. We will highlight that the deleterious effects of MNPs on female reproductive health have been mostly documented in animal models. Studies have demonstrated that MNPs accumulate in ovarian tissue, disrupt hormonal signaling, and induce oxidative stress, leading to hormonal irregularities, ovarian atrophy, and increased androgen levels. Additionally, there is accumulating evidence that not only are MNPs a concern by themselves, but they are also carriers of endocrine-disrupting chemicals (EDCs) which further exacerbate reproductive dysfunction. While animal models demonstrate reproductive toxicity from MNP exposure, there are gaps in our knowledge on whether these findings can be translated to humans. Human clinical trials to directly determine the impact of MNPs are unethical because the evidence suggests MNP exposure may be detrimental to health. In this review, we highlight gaps in our knowledge and suggest areas which need further research.