Plastic pollution in human reproduction: shall we worry?

Micro- and nanoplastics (MNPs) 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 regarding reproductive health and pregnancy outcomes. Research has shown the presence of MNPs in human placenta, fetal meconium, and amniotic fluid, confirming their ability to reach the fetal compartment, potentially increasing risks for fetal development. In females, MNPs have also been detected in follicular fluid, although their specific effects remain to be fully clarified. In vitro studies have reported MNP-induced placental vascular damage, while murine models suggest impaired ovarian function, reduced oocyte quality, and decreased pregnancy rates following MNPs exposure. In males, MNPs have been identified in both testicular tissue and semen. Animal studies report decreased sperm count and quality, likely due to oxidative stress, hormonal disruption, and inflammation. Various techniques are available for detecting MNPs 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