Endocrine-disrupting chemicals detected in breast milk and infant urine through 6 months of age

Exposure to endocrine-disrupting chemicals (EDCs) begins early in life and may continue throughout infancy, according to findings from the LIFE-MILCH project presented at ENDO 2026, the Endocrine Society's annual meeting in Chicago. Investigators reported the presence of multiple classes of EDCs in breast milk and infant urine samples collected from birth through 6 months of age, raising concerns about ongoing environmental exposures during a critical developmental period.^1,2

The study was 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 in Italy. Researchers evaluated samples from 336 mother-infant pairs enrolled in the LIFE-MILCH project, a prospective investigation examining environmental chemical exposures during early life. Healthy mothers with uncomplicated pregnancies were enrolled at centers in Parma, Reggio Emilia, and Cagliari, Italy. Breast milk and infant urine samples were collected at approximately 1 month, 3 months, and 6 months after delivery.

The investigators quantified more than 50 chemicals using ultra-performance liquid chromatography tandem mass spectrometry. The analysis included bisphenols, polycyclic aromatic hydrocarbons, phthalates and their metabolites, parabens, polar pesticides, and pyrethroids.

What did researchers find in breast milk and infant urine?

Among the bisphenols, bisphenol A (BPA) was the most frequently detected compound in breast milk. BPA was identified in 51.2% of breast milk samples collected at 1 month postpartum and 49.8% of samples collected at 6 months. Detection in infant urine increased over time, rising from 32.9% at birth to 67.6% at 6 months. Bisphenol S (BPS), often used as a replacement for BPA, was also detected in both breast milk and infant urine, with frequencies increasing during follow-up.

Which endocrine-disrupting chemicals were detected most often?

Phthalates were among the most commonly detected chemicals. Dibutyl phthalate was identified in 90.2% of breast milk samples at 1 month postpartum and 86.5% at 6 months postpartum. In infant urine, detection increased from 30.3% at birth to 79.4% by 6 months of age. Parabens were also frequently identified. Methylparaben and ethylparaben were present in more than half of breast milk samples and increased in infant urine over time.

What do the findings suggest about early-life exposure?

The researchers additionally reported measurable exposure to glufosinate, a herbicide, in both breast milk and infant urine. Polycyclic aromatic hydrocarbons were rarely detected in breast milk but were identified more consistently in infant urine samples. Overall, approximately half of detectable EDC measurements exceeded the limit of quantification, and the presence of chemicals in breast milk increased the likelihood that the same compounds would be detected in infant urine. Investigators noted that additional environmental sources likely contributed to exposure as infants aged.

“Breast milk is the optimal nutritional source for any child and must be protected as it is a vehicle of environmental contaminants,” Street said in a statement accompanying the findings. “Infancy represents a critical window of exposure since effects are magnified at this age with damage becoming evident after many years.”

Why is reducing exposure during infancy important?

According to the investigators, many of the detected chemicals are associated with dietary exposures as well as products used for personal and household care. Prior studies have linked exposure to EDCs with neurodevelopmental effects, hormonal alterations, changes in growth patterns, weight gain, and obesity. The researchers noted that infancy represents a particularly vulnerable period because developmental processes occurring during the first months of life may be susceptible to environmental influences.

The findings have prompted a prevention campaign in Italy aimed at reducing exposure to EDCs. Street reported that several stakeholders have already signed agreements to monitor and reduce the presence of these chemicals in their products. Researchers are currently evaluating the outcomes of those efforts.

“Breast milk is the optimal nutritional source for any child and must be protected as it is a vehicle of environmental contaminants,” Street reiterated. The investigators concluded that the results support expanded biomonitoring programs and the development of prevention strategies designed to reduce environmental exposures during early life. “The researchers urge public health officials to reduce exposure to EDCs and create preventive strategies to protect breast milk in a changing world.”

References

1. Street ME, Shulhai AM, Pelosi A, et al. Endocrine-disrupting chemicals in breast milk and infant urine samples from birth to 6 months of life: findings from the LIFE-MILCH project. Presented at: ENDO 2026; June 13, 2026; Chicago, IL.

2. Endocrine Society. EDCs Found in Breast Milk and Infant Urine Up to Age 6 Months. Newswise. June 13, 2026. Accessed June 23, 2026. https://www.newswise.com/articles/edcs-found-in-breast-milk-and-infant-urine-up-to-age-6-months