US Universities' Landmark Lancet Study Links Phthalates to 8% of Preterm Births

NYU Researchers Lead Global Effort Linking Plastic Chemicals to Millions of Preterm Births

A groundbreaking study published in The Lancet's eClinicalMedicine journal has quantified the devastating impact of phthalates—chemicals commonly used to make plastics more flexible—on preterm births worldwide, attributing over 8% of cases to exposure from these ubiquitous substances. Led by researchers at New York University Grossman School of Medicine, the analysis estimates that di-2-ethylhexyl phthalate (DEHP) alone contributed to nearly 2 million preterm births in 2018, including tens of thousands in the United States. This revelation underscores the pivotal role US universities are playing in uncovering environmental health risks through rigorous, interdisciplinary research.118

Preterm birth, defined as delivery before 37 weeks of gestation, affects approximately 10% of pregnancies in the US, leading to higher risks of neonatal complications, long-term disabilities, and substantial healthcare costs. The study highlights how phthalates, found in everything from food packaging and personal care products to medical tubing and flooring, leach into the body via ingestion, inhalation, and skin contact, acting as endocrine disruptors that interfere with hormonal balance critical for pregnancy.117

At the forefront is NYU's Division of Environmental Pediatrics, directed by Leonardo Trasande, MD, MPP—a professor of pediatrics and population health whose team has pioneered efforts to link everyday chemical exposures to child health outcomes. Trasande, also affiliated with NYU's Wagner School of Public Service, emphasizes that "regulating phthalates one at a time is like playing Whac-A-Mole; we need class-wide oversight."116

Understanding Phthalates: Sources, Exposure Pathways, and Biological Mechanisms

Phthalates, or phthalic acid esters, are synthetic chemicals added to polyvinyl chloride (PVC) plastics to enhance durability and flexibility. Diethylhexyl phthalate (DEHP), diisononyl phthalate (DiNP), diisodecyl phthalate (DiDP), and di-n-octyl phthalate (DnOP) are among the most prevalent, with DEHP historically dominant until partial regulatory restrictions prompted shifts to alternatives like DiNP, which the new research shows may be equally hazardous.118

Exposure occurs through contaminated food (e.g., fatty foods packaged in phthalate-containing materials), household dust, cosmetics, and even medical devices. In pregnant women, these chemicals cross the placenta, disrupting steroidogenesis, inducing oxidative stress, and promoting inflammation—key pathways to preterm labor. Hazard ratios from prior cohorts indicate a 45% increased risk per log-unit rise in DEHP exposure above threshold levels, with DiNP showing even stronger associations (HR 2.25).117

University labs like NYU's have developed advanced biomonitoring techniques using urine metabolite analysis (e.g., MEHP for DEHP, MCOP for DiNP) to quantify population-level risks, drawing from datasets like the National Health and Nutrition Examination Survey (NHANES).

NYU Grossman School of Medicine: Pioneering Environmental Pediatrics Research

NYU Grossman School of Medicine's Division of Environmental Pediatrics stands as a beacon in this field, with Trasande's leadership driving policy-relevant studies. The division's Center for the Investigation of Environmental Hazards integrates epidemiology, toxicology, and economics to assess chemical burdens, including phthalates' role in preterm birth, obesity, and neurodevelopment. Recent work estimates phthalate-attributable preterm births cost the US billions annually in medical care and lost productivity.169

Associate research scientist Sara Hyman, lead author on the Lancet paper, exemplifies the division's talent, using population attributable fraction models to project global impacts. NYU's interdisciplinary approach—spanning pediatrics, population health, and public service—equips students and faculty to translate findings into actionable policy, influencing regulations like the US Consumer Product Safety Improvement Act.116

This higher education hub not only produces seminal research but trains the next generation through residencies and fellowships focused on environmental health disparities.

The NIH ECHO Program: A Collaborative Network of US Universities

The National Institutes of Health's Environmental influences on Child Health Outcomes (ECHO) program unites over a dozen US universities in massive cohort studies. The 2024 Lancet Planetary Health paper, pooling data from 5,006 mother-child pairs across 13 cohorts, found phthalic acid, DiDP, DiNP, and DnOP most strongly linked to reduced gestational age, estimating 56,595 attributable US preterm births in 2018 at $3.84 billion in costs.117

• New York University Grossman School of Medicine: Lead analysis on phthalate mixtures.
• Rutgers University School of Public Health: Biostatistics and epidemiology.
• Johns Hopkins Bloomberg School of Public Health: Environmental health engineering.
• Emory University School of Medicine: Gynecology and obstetrics.
• Columbia University Mailman School: Environmental health sciences.
• University of Michigan School of Public Health: Key phthalate exposure modeling.
• University of California, San Francisco: Reproductive sciences.
• And others including Penn State, Dartmouth, Wayne State, University of Washington, UIUC, UNC Chapel Hill.

This consortium exemplifies how US higher education fosters collaborative science, leveraging diverse cohorts for robust findings on trimester-specific vulnerabilities.

Photo by Michael D Beckwith on Unsplash

Shocking Statistics: Phthalates' Burden on US Maternal and Neonatal Health

In the US, preterm birth rates hover at 10.1%, with phthalates implicated in thousands annually. The 2026 Lancet study pegs DEHP at 16,700 and DiNP at 66,600 US preterm births in 2018, while ECHO data suggests broader impacts from replacements. Costs encompass NICU stays ($4,300 per day), lifelong disabilities, and productivity losses—totaling billions.118117

Higher burdens fall on low-income and minority communities due to greater exposure via consumer products.

Beyond Births: Long-Term Health and Economic Ramifications

Preterm infants face respiratory distress, cerebral palsy, and cognitive delays, amplifying lifetime costs. University research links phthalates to childhood obesity, asthma, and reproductive issues, with Trasande's team estimating cardiovascular mortality ties. For higher ed, this spurs programs in public health and toxicology.ECHO Lancet analysis

Other US Universities Advancing Phthalate Research

Rutgers Environmental and Occupational Health Sciences Institute leads cohort studies on mixtures. University of Michigan's phthalate lab examines Puerto Rico's high preterm rates. UGA and others explore regional disparities. These efforts train grad students in biomonitoring and epidemiology.39

Higher Ed Campuses Tackle Phthalates Through Sustainability Initiatives

US colleges pioneer phthalate reduction: NYU's green purchasing bans PVC; Berkeley's HERMOSA studies cosmetics exposures; zero-waste programs at Carleton reduce plastics. These align research with action, educating students on safer alternatives.Campus healthier initiatives

Photo by stephan hinni on Unsplash

Opportunities for Students: Careers in Environmental Health Research

US universities offer fellowships, PhDs in env pediatrics at NYU, JHU. Programs equip students to combat endocrine disruptors, with demand for experts in policy and toxicology surging.

Path Forward: Policy, Innovation, and University-Led Solutions

Calls for class-wide bans echo from NYU. Universities advocate via NIH, EPA. Future: safer plastics, better regs. US higher ed drives change.