Tiny plastic particles can cross a placenta-like barrier and disrupt hormones essential for pregnancy and foetal development, according to a laboratory cell model study published in Molecular and Cellular Endocrinology.
Researchers built a tri-culture model combining three types of human cells to represent the maternal-placental-foetal interface: BeWo cells for the placental barrier, HUVEC cells for foetal blood vessels, and H295R cells for foetal adrenal glands. They tested several common plastic types, including PMMA (a transparent glass alternative), PET (used in bottles), PVC (used in pipes and packaging), and polystyrene (used in packing materials).
All plastic types tested were able to move from the maternal side through the placental barrier to the foetal side. Smaller particles crossed more easily than larger ones, with PMMA showing the largest measured transfer at approximately 11%, reaching the foetal-side chamber after three days.
High-powered 3D microscopy revealed that plastics had entered cells rather than simply floating around them. Polystyrene particles between 50 nm and 200 nm were found inside both placental and foetal blood vessel cells.
The micro- and nanoplastics also acted as endocrine disruptors. Polystyrene caused a reduction in oestrogen levels and decreased expression of the CYP17 gene, which is essential for steroid hormone synthesis. Most other plastics tested reduced levels of etiocholanolone, a hormone that sends signals to the developing foetus.
Microplastics have previously been detected in human placenta, amniotic fluid, and infant stool, as well as in everyday foods and drinks. The researchers noted that further work is needed to understand the implications for foetal development and how these particles disrupt hormone production pathways.
Source: Medical Xpress / Molecular and Cellular Endocrinology (2026)
