Microplastics in Neonatal Intensive Care: Exposure Pathways, Measurement, and Source Attribution

Preterm and critically ill infants rely on plastic-containing medical systems for respiratory support, nutrition, vascular access, medication delivery, and monitoring. These systems are potential sources of microplastic (MP) exposure, although evidence varies by route. This narrative review examines intravascular, enteral, and respiratory exposure in neonatal intensive care unit (NICU) and considers how to measure and interpret these exposures in neonates. Evidence is strongest for the intravascular pathway, more limited for the enteral pathway, and currently insufficient to characterize either device-derived respiratory exposure or ambient-air exposure in the NICU. Across all three pathways, differences in analytical methods, particle-size ranges, contamination control, and source attribution make it difficult to determine what particles reach the infant and where they originate. Interpretation is further complicated because the most premature and critically ill infants receive the most intensive and prolonged device-dependent care. This makes it difficult to separate treatment-associated exposure from the effects of prematurity and illness severity, which also determine treatment intensity and influence neonatal outcomes. Addressing this problem will require quantitative studies that determine what particles reach the infant, identify their sources, and assess whether they are also detected in neonatal specimens.