Placental microplastics contamination and its impact on thyroid function in newborns

Area of Science:

• Environmental Health
• Endocrinology
• Toxicology

Background:

• Microplastics (MPs) are increasingly detected in human tissues, including the placenta.
• Thyroid hormones are crucial for fetal growth and development.
• Potential risks of MPs to newborn health via thyroid function disruption are a growing concern.

Purpose of the Study:

• To investigate the association between placental microplastic levels and thyroid hormone profiles in newborns.
• To assess the impact of specific microplastic types (PVC, PP, PBS) on fetal thyroid hormone concentrations.

Main Methods:

• A cohort study of 1250 mother-child pairs (2022-2024).
• Measurement of umbilical cord blood thyroid hormones (free thyroxine [T4], free triiodothyronine [T3], thyroid-stimulating hormone [TSH]).
• Quantification of placental microplastics (PVC, PP, PBS) and analysis using multivariable regression models (MLR), quantile g-computation (g-comp), and Bayesian Kernel Machine Regression (BKMR).

Main Results:

• Significant reductions in newborn T4 and TSH levels were associated with exposure to PVC, PP, and PBS microplastics.
• Decreases in the T4/T3 ratio were observed with PVC and PP exposure.
• Polypropylene (PP) was the only microplastic type linked to increased T3 levels.
• Dose-response relationships were identified, with higher MP exposure correlating with lower T4 and T4/T3 ratios.

Conclusions:

• Placental microplastic exposure is associated with altered thyroid hormone profiles in newborns.
• Key findings indicate a reduction in T4 and T4/T3 ratio, suggesting potential disruption of thyroid function.
• The study highlights the need for further research into the long-term health implications of prenatal MP exposure.