The Silent Perinatal Passage: A PRISMA 2020 Systematic Review of Transplacental Transfer of PFAS and Microplastics and Fetal Endocrine Disruption

Introduction:
Emerging contaminants (ECs), particularly per- and polyfluoroalkyl substances (PFAS) and microplastics (MPs), are increasingly detected in human biological matrices. During pregnancy, transplacental transfer may expose the fetus to toxic compounds during a critical developmental window. However, this exposure route remains insufficiently integrated into developmental toxicology and One Health risk assessment frameworks.

Methods :
A PRISMA 2020-compliant systematic review was conducted using PubMed, Scopus, Web of Science, and Ecotox databases (January 2015–March 2025). Eligible studies included original human research quantifying PFAS or MPs in paired maternal–fetal samples (placenta, cord blood, or meconium) and evaluating endocrine-related outcomes. Two independent reviewers performed study selection and quality assessment.

Results:
Among 1,482 screened records, 18 studies met the inclusion criteria. PFAS were detected in 89–100% of placental and cord blood samples, with cord-to-maternal transfer ratios frequently exceeding 0.5 for long-chain compounds. MPs, mainly polypropylene, polyvinyl chloride, and polybutylene succinate, were frequently identified in placental tissues. Higher MP exposure was associated with decreased umbilical cortisol levels (β = –2.20 ng/mL per IQR increase, p < 0.01), increased dehydroepiandrosterone concentrations (β = +0.07 ng/mL, p < 0.01), and a reduced glucocorticoid/androgen ratio (β = –4.37, p < 0.01), suggesting fetal endocrine disruption. To our knowledge, no previous systematic review has jointly evaluated PFAS and MPs transplacental transfer in relation to endocrine outcomes.

Conclusions:
Current evidence indicates that transplacental exposure to PFAS and MPs is widespread and associated with alterations in fetal endocrine signaling pathways. These findings support the integration of developmental and transplacental toxicology into One Health risk assessment frameworks and highlight the need for standardized biomonitoring strategies during pregnancy.