Sources of clinically significant neonatal intensive care unit phthalate exposure

In the United States each year, more than 300,000 infants are admitted to neonatal intensive care units (NICU) where they are exposed to a chemical-intensive hospital environment during a developmentally vulnerable period. Although multiple studies have demonstrated elevated phthalate biomarkers in NICU patients, specific sources of NICU-based phthalate exposure have not been identified. In this study, premature newborns with birth weight <1500 g were recruited to participate in a prospective environmental health cohort during the NICU hospitalization. Exposure to specific NICU equipment was recorded daily during the NICU hospitalization. One hundred forty-nine urine specimens from 71 infants were analyzed for phthalate metabolites using high-performance liquid chromatography/tandem mass spectrometry. In initial analyses, exposure to medical equipment was directly related to phthalate levels, with DEHP biomarkers 95–132% higher for infants exposed to specific medical equipment types compared to those without that equipment exposure (p < 0.001–0.023). This association was mirrored for clinically relevant phthalate mixtures whether composed of DEHP metabolites or not (p = 0.002–0.007). In models accounting for concurrent equipment use, exposure to respiratory support was associated with DEHP biomarkers 50–136% higher in exposed compared to unexposed infants (p = 0.007–0.036). Phthalate mixtures clinically relevant to neurobehavioral development were significantly associated with non-invasive respiratory support (p = 0.008–0.026). Feeding supplies and intravenous lines were not significantly associated with clinically important phthalate mixtures. Respiratory support equipment may be a significant and clinically relevant NICU source of phthalate exposure. Although manufacturers have altered feeding and intravenous supplies to reduce DEHP exposure, other sources of exposure to common and clinically impactful phthalates persist in the NICU.