The presence of endocrine-disrupting chemicals (EDCs) in both breast milk and the urine of infants from birth through the first six months of life has emerged as a significant public health concern, according to comprehensive research presented at ENDO 2026. The study, unveiled at the Endocrine Society’s annual meeting in Chicago, Illinois, provides a sobering look at how environmental contaminants penetrate the earliest stages of human development. Lead researcher Maria Elisabeth Street, MD, PhD, an associate professor and director of the Division of Pediatric Endocrinology at the University of Parma and University Hospital of Parma, emphasized that while breast milk remains the gold standard for infant nutrition, its role as a potential vehicle for chemical exposure necessitates urgent protective measures.
Infancy is widely regarded by medical professionals as a "critical window" of biological vulnerability. During this period, the endocrine system—the complex network of glands and hormones that regulates growth, metabolism, and development—is particularly sensitive to external interference. Dr. Street noted that because infants are in a state of rapid physiological change, the effects of chemical exposure are often magnified, potentially leading to developmental damage that may not manifest until much later in life.
The LIFE-MILCH Project: Methodology and Scope
The findings presented at the conference were derived from the LIFE-MILCH project, a multi-center study designed to evaluate the impact of environmental endocrine disruptors on mother-infant pairs. The researchers monitored 336 pairs, collecting biological samples at three distinct intervals: one month, three months, and six months postpartum. This longitudinal approach allowed the team to track how chemical concentrations shifted over time as the infants aged and as maternal exposure patterns evolved.
The scope of the chemical analysis was extensive, covering more than 50 different substances known or suspected to interfere with hormonal signaling. These included:
- Bisphenols: Specifically Bisphenol A (BPA) and its common substitute, Bisphenol S (BPS).
- Phthalates: Plasticizers used to increase the flexibility of plastics, as well as their metabolites.
- Parabens: Preservatives frequently found in cosmetics and personal care products.
- Polycyclic Aromatic Hydrocarbons (PAHs): Chemicals typically produced by the incomplete combustion of organic matter.
- Pesticides: Including polar pesticides and pyrethroids like Glufosinate.
By analyzing both breast milk and infant urine, the researchers were able to assess not only the "input" of chemicals via maternal transfer but also the "internal load" present within the infants’ systems.
Bisphenols and the "BPA-Free" Paradox
One of the most striking aspects of the study was the persistent presence of Bisphenol A (BPA) despite increased regulatory scrutiny and the rise of "BPA-free" labeling. BPA was detected in 51.2% of breast milk samples at the one-month mark and remained high at 49.8% after six months. Even more concerning was the detection rate in infants; while roughly one-third of infants tested positive for BPA in their urine at birth, this figure skyrocketed to 67.6% by the time they reached six months of age.
The study also highlighted the emergence of Bisphenol S (BPS), a chemical often used to replace BPA in manufacturing. BPS was found in 10.7% of breast milk samples at one month, rising to 18.3% at six months. In infants, BPS was detected in 22.4% of urine samples at birth, nearly doubling to 41.2% by the six-month mark. This upward trend suggests that infants are increasingly exposed to these "replacement" chemicals through their environment, even as legacy chemicals like BPA remain prevalent.
Phthalates and Parabens: Ubiquitous Environmental Contaminants
Phthalates, which are used in everything from food packaging to medical tubing, showed the highest rates of detection in the study. Dibutyl phthalate (DBP) was found in a staggering 90.2% of breast milk samples at one month and 86.5% at six months postpartum. The corresponding urine samples from infants showed a dramatic increase in phthalate detection, moving from 30.3% at birth to 79.4% at six months.
Parabens followed a similar trajectory. Methylparaben (MePB) and ethylparaben (EtPB) were found in more than half of the breast milk samples (56.2% and 52.6%, respectively) by the six-month mark. The researchers observed that the concentration of these chemicals in infant urine samples increased steadily over time, pointing to cumulative exposure from the household environment and personal care products used by both the mother and the infant.
Pesticides and Industrial Byproducts
The study also shed light on the presence of glufosinate, a broad-spectrum herbicide. Glufosinate was detected in 27.4% of breast milk samples at one month and 31.9% at three months. In infants, the detection rate was 44.7% at birth, suggesting prenatal exposure, and remained significant at 38.2% at six months of age.
Interestingly, while Polycyclic Aromatic Hydrocarbons (PAHs) were rarely detected in breast milk, they were consistently found in infant urine, with detection rates reaching up to 27.7%. This suggests that infants may be absorbing these chemicals through pathways other than breastfeeding, such as inhalation of indoor air or contact with contaminated dust and surfaces.
Biological Implications and Health Risks
The presence of these chemicals is not merely a matter of environmental "noise"; it carries profound implications for pediatric health. According to Dr. Street, the data collected through the LIFE-MILCH project links EDC exposure to several adverse health outcomes:
- Neurodevelopmental Issues: EDCs can interfere with thyroid hormones and other signaling pathways essential for brain development, potentially affecting cognitive function and behavior.
- Hormonal Imbalance at Birth: Exposure can trigger premature hormonal activation, disrupting the natural endocrine milestones of the neonatal period.
- Androgenization: Some chemicals have been linked to the development of male reproductive characteristics in female infants or the disruption of normal reproductive development in males.
- Metabolic Dysfunction: There is growing evidence that EDC exposure during infancy can alter growth trajectories, leading to increased risks of childhood obesity and metabolic syndrome.
"These chemicals act as ‘hormone mimics’ or ‘hormone blockers,’" explained Dr. Street. "In the delicate environment of a developing infant, even minute concentrations can send incorrect signals to the body’s cells, leading to permanent changes in how the body grows and functions."
Sources of Exposure and the Path Forward
The researchers identified nutrition habits and the use of personal and household care products as the primary drivers of EDC levels in the study participants. This includes the consumption of processed foods packaged in plastics, the use of scented lotions and soaps containing parabens, and the presence of household dust contaminated with flame retardants and plasticizers.
In response to these findings, a prevention campaign has been launched in Italy to educate parents and healthcare providers on how to minimize exposure. Dr. Street revealed that several stakeholders, including manufacturers and local government bodies, have signed agreements to monitor and reduce the use of these chemicals in consumer products. The results of this prevention campaign are currently under evaluation, with the hope that it will serve as a model for other nations.
Global Context and Scientific Analysis
The findings from ENDO 2026 align with a growing body of international research highlighting the "chemical burden" carried by the modern population. Organizations such as the World Health Organization (WHO) and the United Nations Environment Programme (UNEP) have previously characterized EDCs as a global threat.
The Italian study is particularly significant because of its longitudinal design and its focus on the transition from the womb to the first six months of life. Most previous studies have focused on either prenatal exposure or adult levels; the LIFE-MILCH data fills a critical gap in understanding how the "exposome"—the sum of environmental exposures over a lifetime—begins to accumulate immediately after birth.
From a policy perspective, the study underscores the limitations of current chemical regulations. While the European Union’s REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulation is among the strictest in the world, the high detection rates of phthalates and bisphenols in this study suggest that existing bans and restrictions may not be sufficient to protect the most vulnerable populations.
Conclusion and Recommendations
The researchers concluded their presentation with a call to action for public health officials and policymakers. They advocate for a multi-pronged strategy to protect the integrity of breast milk and infant health:
- Stricter Regulation: Moving beyond "BPA-free" to regulate entire classes of chemicals (such as all bisphenols) to prevent the "regrettable substitution" of one harmful chemical for another.
- Enhanced Labeling: Providing consumers with clearer information about the presence of EDCs in household products and food packaging.
- Public Education: Informing expectant and new parents about lifestyle changes—such as reducing plastic use and choosing fragrance-free products—that can lower chemical loads.
- Continued Monitoring: Establishing long-term surveillance programs to track EDC levels in breast milk and pediatric populations globally.
As Dr. Street concluded, "Breast milk is a precious resource that provides incomparable benefits to infants. Our goal is not to discourage breastfeeding, but to advocate for a cleaner environment that ensures this vital source of life remains as pure as possible for the next generation."
