Researchers presenting at ENDO 2026, the Endocrine Society’s annual meeting in Chicago, have unveiled startling data regarding the presence of endocrine-disrupting chemicals (EDCs) in both breast milk and the urine of infants during the first six months of life. The study, led by Maria Elisabeth Street, MD, PhD, associate professor and director of the Division of Pediatric Endocrinology at the University of Parma and University Hospital of Parma, Italy, underscores a growing public health concern regarding how environmental contaminants are transmitted to the most vulnerable populations. By analyzing the exposure levels of more than 50 different chemicals, the research team identified a persistent presence of bisphenols, phthalates, and parabens, highlighting a direct link between modern lifestyle products and internal biological contamination.
The findings come at a time when global health organizations are increasingly scrutinizing the long-term impact of "forever chemicals" and plasticizers on human development. According to the research team, infancy represents a "critical window of exposure" during which the biological systems of a child are highly sensitive to hormonal interference. Because infants are in a state of rapid growth and physiological development, the effects of these chemicals are often magnified, potentially leading to health complications that may not become fully evident until decades later.
The LIFE-MILCH Project: Study Design and Methodology
The data presented at the conference was derived from the LIFE-MILCH project, an expansive longitudinal study designed to monitor the interactions between maternal lifestyle, environmental exposure, and infant health. The researchers followed 336 mother-infant pairs, collecting biological samples at three distinct intervals: one month, three months, and six months postpartum. This timeline allowed the team to track how chemical concentrations shifted as infants transitioned through different stages of early development and as maternal exposure continued through the breastfeeding period.
The scope of the chemical analysis was comprehensive. Scientists screened for more than 50 substances known or suspected to interfere with the endocrine system. These included bisphenol A (BPA) and its common substitute bisphenol S (BPS), polycyclic aromatic hydrocarbons (PAHs), phthalates and their various metabolites, parabens used in personal care products, and a range of pesticides including polar pesticides and pyrethroids. By measuring these substances in both breast milk and infant urine, the study provided a dual perspective on how chemicals enter the infant’s body and how effectively they are being processed or accumulated.
Detailed Findings: Bisphenols and Synthetic Contaminants
One of the most significant findings involved the detection of bisphenols, chemicals widely used in the production of plastics and epoxy resins. Bisphenol A (BPA) was detected in 51.2% of breast milk samples at the one-month mark and remained nearly as prevalent at six months, appearing in 49.8% of samples. Perhaps more concerning was the trajectory of BPA in the infants themselves. While approximately one-third of infants had detectable BPA in their urine shortly after birth, that number surged to 67.6% by the time the infants reached six months of age.
The study also shed light on Bisphenol S (BPS), a chemical frequently used as a "safer" alternative to BPA in consumer products. However, the data suggests that BPS is also becoming a common contaminant. BPS was found in 10.7% of breast milk samples at one month, rising to 18.3% at six months. In infants, the detection rate of BPS in urine rose from 22.4% at birth to 41.2% at six months. This trend suggests that current regulatory shifts away from BPA toward other bisphenols may not be reducing the overall chemical burden on infants but rather shifting the profile of the contaminants they encounter.
Prevalence of Parabens and Phthalates
The research also highlighted the ubiquity of parabens, which are commonly used as preservatives in cosmetics, lotions, and shampoos. Methylparaben (MePB) and ethylparaben (EtPB) were detected in more than half of the breast milk samples analyzed. At one month postpartum, MePB was found in 51.2% of samples, while EtPB was found in 42.3%. By the six-month mark, these figures rose to 56.2% and 52.6%, respectively. The study noted a corresponding increase in the concentration of these chemicals in infant urine over the six-month period, suggesting that daily contact with personal care products by both mothers and infants contributes to a steady rise in internal exposure.
Phthalates, a group of chemicals used to make plastics more flexible and durable, showed some of the highest detection rates 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. The presence of phthalates in infant urine also saw a dramatic increase, rising from a 30.3% detection rate at birth to 79.4% by six months of age. Because phthalates are known to interfere with testosterone production and reproductive development, their high prevalence in such a large majority of the study group has raised significant alarms among pediatric endocrinologists.
Pesticides and Environmental Hydrocarbons
Beyond plasticizers and preservatives, the study identified agricultural and industrial contaminants. Glufosinate, a broad-spectrum herbicide, was detected in roughly 27% to 32% of breast milk samples across the first three months. In infant urine, the detection rate was 44.7% at birth, remaining high at 38.2% at six months. The presence of such pesticides in breast milk highlights the impact of dietary choices and environmental proximity to agricultural runoff on maternal health.
Polycyclic aromatic hydrocarbons (PAHs), which are typically byproduct pollutants from the combustion of organic matter like gasoline or wood, were rarely detected in breast milk. However, they were consistently found in infant urine, with detection rates reaching as high as 27.7%. This suggests that while breast milk may not be the primary vehicle for PAHs, infants are likely inhaling or otherwise absorbing these chemicals from the ambient environment, such as air pollution or household dust.
Health Implications: Growth, Development, and Hormonal Disruption
The clinical significance of these findings lies in the known physiological effects of EDCs. Dr. Street noted that exposure to these chemicals is linked to a variety of adverse health outcomes. One of the primary concerns is neurodevelopmental interference, as many EDCs can cross the blood-brain barrier and disrupt the hormonal signaling required for proper brain architecture.
Furthermore, the study linked EDC exposure to "androgenization"—the development of male reproductive characteristics in ways that may be atypical—and hormonal activation at birth. There is also a strong correlation between EDC exposure and metabolic changes, including altered growth patterns, weight gain, and an increased risk of childhood obesity. Because EDCs can mimic or block natural hormones like estrogen and testosterone, they can "reprogram" a child’s endocrine system, setting the stage for chronic conditions later in life, such as infertility, thyroid dysfunction, and metabolic syndrome.
The Role of Nutrition and Household Products
A key takeaway from the LIFE-MILCH data is that the presence of these chemicals is largely tied to everyday habits. Dr. Street emphasized that the majority of the EDCs found in the samples are associated with nutrition habits and the specific products used for personal and household care. This includes the use of plastic containers for food storage, the consumption of processed foods packaged in materials containing BPA or phthalates, and the application of scented lotions and cleaning agents.
While the study identifies breast milk as a vehicle for these contaminants, the researchers were careful to reaffirm that breastfeeding remains the optimal nutritional source for infants. The goal of the research is not to discourage breastfeeding, but rather to advocate for the protection of breast milk as a biological resource. By identifying how these chemicals enter the maternal system, public health officials can provide better guidance on how to minimize exposure through lifestyle modifications.
Official Responses and Prevention Strategies
In response to the data, a prevention campaign has been launched in Italy, where the study was conducted. This campaign aims to educate parents and healthcare providers on reducing the use of endocrine-disrupting products. According to Dr. Street, the results of this intervention are currently under evaluation. Additionally, the study’s findings have prompted a series of agreements with industrial stakeholders in Italy. Several companies have signed on to monitor their supply chains more closely and work toward reducing the concentration of these harmful chemicals in consumer products.
However, the researchers argue that voluntary agreements and individual lifestyle changes are only part of the solution. They have issued a call to action for public health officials worldwide to implement more rigorous regulatory frameworks. This includes stricter limits on the use of phthalates and bisphenols in food packaging and a more precautionary approach to the approval of new chemical compounds used in household goods.
Analysis of Broader Implications and Future Outlook
The LIFE-MILCH project serves as a microcosm of a global environmental health crisis. As chemical production continues to expand, the "chemical footprint" in human biology is becoming more complex. The fact that detection rates for many of these chemicals increased over the first six months of life suggests that the environment an infant is born into is increasingly saturated with synthetic compounds.
From a journalistic and policy perspective, this study challenges the "BPA-free" marketing narrative. The presence of BPS and various phthalate metabolites suggests that when one chemical is regulated or stigmatized, industry often pivots to structurally similar alternatives that may carry similar risks. This "regrettable substitution" underscores the need for class-based chemical regulation rather than a substance-by-substance approach.
As the scientific community continues to analyze the data from ENDO 2026, the focus will likely shift toward long-term follow-ups of the LIFE-MILCH cohort. Tracking these children into adolescence and adulthood will provide definitive evidence of how early-life EDC exposure translates into long-term health outcomes. In the interim, the study stands as a stark reminder that the protection of the next generation requires a fundamental shift in how society manages environmental and chemical safety. Public health strategies must now evolve to treat the preservation of uncontaminated breast milk as a primary objective of environmental policy, ensuring that the "optimal nutritional source" for children remains as pure as nature intended.
