Relationship between micro- and nanosized plastics in cord blood and birth weight and gestational age of newborns

Pervasive detection of micro- and nanosized plastics (MNPs) in biosphere and their potential human health impacts have raised significant public and scientific concerns. Despite growing evidence of MNP presence in human cord blood, their effects on fetal development and birth outcomes remain poorly understood. This study investigated the occurrence and concentrations of 11 types of MNPs in 151 umbilical cord blood samples using pyrolysis-gas chromatography-mass spectrometry and evaluated their associations with neonatal birth size and gestational age. Results showed that polyethylene (PE), polystyrene (PS), polypropylene (PP), and polycarbonate were detected in over 80% of cord blood samples, with PE being the most abundant (mean 4.79 μg/g) MNP, followed by PS (1.81 μg/g) and PP (0.89 μg/g). Quantile-based g-computation showed that combined exposure to MNPs was negatively correlated with birth weight (β = -29.4, 95% CI -51.5, -7.72; p = 0.028), birth length (β = -0.17, 95% CI -0.29, -0.059; p = 0.023), head circumference (β = -0.23, 95% CI -0.30, -0.15; p = 0.016), and thoracic circumference (β = -0.15, 95% CI -0.26, -0.050; p = 0.039) of infants. Mixture exposure to MNPs was also negatively correlated with gestational age (β = -0.26, 95% CI -0.41, -0.11; p = 0.018), and PE and PS served as the primary contributors. These findings deepen the understanding of the risks that exposure to certain MNPs may pose to a developing fetus.