Plastic pollution in human reproduction: should we worry?

Micro- and nanoplastics (MNP) are pervasive pollutants, detected in every ecosystem. Human exposure is extensive, and their capacity to cross biological barriers and accumulate in tissues raises growing concerns about reproductive health and pregnancy outcomes. Research has shown the presence of MNP in human placenta, fetal meconium and amniotic fluid, confirming their ability to reach the fetal compartment, potentially increasing risks for fetal development. In women, MNP have also been detected in follicular fluid, although their specific effects remain to be determined. In-vitro studies have reported MNP-induced placental vascular damage, whereas murine models suggest impaired ovarian function, reduced oocyte quality and decreased pregnancy rates after MNP exposure. In men, MNP have been identified in testicular tissue and semen. Animal studies report decreased sperm count and quality, likely because of oxidative stress, hormonal disruption and inflammation. Various techniques are available for detecting MNP in biological tissues. Mass and Raman spectroscopy are among the most widely used, each offering specific advantages and limitations. Interpreting experimental data also requires caution, as many in-vitro and in-vivo models use unrealistically high doses of pristine polymers lacking environmental additives, potentially limiting the relevance of their findings to real-world exposures.