A Transwell tri-culture in vitro model (BeWo b30 + HUVEC + H295R cells) was used to assess translocation and steroidogenic effects of seven micro- and nanoplastic (MNP) polymers — PS (50, 200, 1000 nm), PMMA, PVC, PA6,6, and PET — applied apically at 1 and 10 μg/mL over 72 hours.
All tested MNPs crossed the feto-placental barrier (PMMA highest at 10.7%, PS50nm at 4.4%); PS1000nm and PS50nm (10 μg/mL) reduced 17-OH-DHP by 36% and 29%, respectively; PET, PMMA, PA6,6, and PVC reduced etiocholanolone by 23–25%; PS1000nm (1 μg/mL) lowered 17β-estradiol by 14%; CYP17 expression decreased with PS200nm and PS1000nm exposure.
- This is an in vitro model; findings may not fully reflect complex in vivo placental physiology. - Custom-made polymers varied widely in size ranges, making direct polymer-to-polymer comparisons difficult. - F-PA6,6 translocation could not be reliably quantified, leaving a gap in polymer-specific data.
MNPs can cross a modeled feto-placental barrier and disrupt steroidogenesis at environmentally plausible concentrations, suggesting a potential endocrine-disrupting risk during pregnancy. Clinicians should be aware of emerging evidence linking plastic exposure to placental hormone disruption, though clinical guidance awaits in vivo confirmation.
