The effects of industrial chemicals bonded to plastic materials in newborns: A systematic review

Background: Phthalates are a family of industrial chemicals noncovalently bonded to plastic materials to enhance flexibility and durability. These compounds are extensively used in a variety of consumer products and even in many medical devices. Newborns present a higher susceptibility to phthalates. Objective: To assess the short- and long-term health consequences of exposure to phthalates during the neonatal period.Methods: Systematic review in accordance with the PRISMA statements. Eligible articles in English language were searched in MEDLINE, Scopus, ISI Web of Science, and Ovid databases using the following terms: "phthalate", "newborn", and "neonate". Unpublished data were searched in ClinicalTrials.gov website. All in vivo studies of any design published before May 16th, 2023 and fulfilling the following criteria were included: 1) investigations in which preterm and/or term newborns underwent one or more measurement of concentrations of phthalates on biological samples taken during the neonatal period; 2) studies in which quantitative measurement of phthalates was related to any kind of health outcome. Subgroup analysis was conducted by type of outcome. The quality assessment was performed according to the criteria from the "NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies".Results: 11,895 records were identified; finally, 5 articles were included for review. A mixture of phthalates was associated with improved performance on the NNNS summary scales of Attention, Handling, and Non-optimal reflexes before NICU discharge. At 2 months' corrected age, some phthalates were positively associated with problem-solving and gross motor abilities; increased levels of mono (2-ethylhexyl) phthalate, mono (2-ethyl-5carboxypentyl) phthalate, and sum of di (2-ethylhexyl) phthalate (DEHP) metabolites ( n-ary sumation 3DEHP and n-ary sumation 4DEHP) were associated with worse fine motor performance. Furthermore, DEHP was associated with transient alteration of gut microbiota and increased IgM production after vaccine. A linear positive association between a mixture of phthalates and slope of the first growth spurt was even reported in preterm newborns. No relationship emerged between phthalates and bronchopulmonary dysplasia. Three studies out of 5 had fair quality.Conclusion: Given some methodological issues and the paucity of related studies, further investigations of flawless quality aimed at clarifying the relationship between early exposure to phthalates and health outcomes are needed.