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Multiple Studies Detect Endocrine-Disrupting Chemicals in Breast Milk and Infant Urine

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Endocrine-Disrupting Chemicals Found in Breast Milk and Infant Urine

Two separate studies have reported the presence of various endocrine-disrupting chemicals (EDCs) in breast milk and infant urine samples, highlighting widespread exposure to these compounds early in life.

Study 1: Multi-Chemical Analysis of Mother-Infant Pairs

A study presented at the Endocrine Society's annual meeting (ENDO 2026) analyzed samples from 336 mother-infant pairs participating in the LIFE-MILCH project. Samples were collected at one, three, and six months after birth.

Common Contaminants Found

The research measured exposure to over 50 chemicals, including bisphenols, polycyclic aromatic hydrocarbons (PAHs), phthalates, parabens, polar pesticides, and pyrethroids. Key findings include:

"BPA was detected in 51.2% of breast milk samples at one month and 49.8% at six months."

  • Bisphenol A (BPA): Detected in 51.2% of breast milk samples at one month and 49.8% at six months. In infant urine, BPA was found in approximately one-third of samples at birth, increasing to 67.6% at six months.
  • Bisphenol S (BPS): Found in 10.7% of breast milk at one month and 18.3% at six months. Infant urine levels rose from 22.4% at birth to 41.2% at six months.
  • Parabens: Methylparaben and ethylparaben were common in breast milk (approximately 51% and 42% at one month; 56% and 53% at six months) and increased in infant urine over time.
  • Phthalates: Dibutyl phthalate was found in 90.2% of breast milk at one month and 86.5% at six months. Urine levels increased from 30.3% at birth to 79.4% at six months.
  • Pesticides: Glufosinate was detected in breast milk at one month (27.4%) and three months (31.9%), and in infant urine at birth (44.7%) and six months (38.2%).

Study 2: Analysis of Breast Milk Samples from Seattle

A peer-reviewed study published in a separate journal analyzed 50 breast milk samples from mothers in Seattle. The chemicals detected included BPA, BPS, melamine, cyanuric acid, and triclosan. The same samples had previously been shown to contain per- and polyfluoroalkyl substances (PFAS) and flame retardants.

Results

"92% of samples contained at least one of the tested antimicrobials or plasticizers."

  • Bisphenols: BPA was found in 74% of samples; BPS was found in 78%.
  • Triclosan: Present in 62% of samples.
  • Melamine: Detected in 92% of samples.
  • Overall: 92% of samples contained at least one of the tested antimicrobials or plasticizers.

Study Limitations and Observations

The Seattle study's small sample size and the demographic profile of participants (higher income, more educated) are noted as limitations. Some chemical levels measured in both studies were below World Health Organization tolerable daily intake limits but have been associated with disease in previous epidemiological research.

Sources and Context

According to Maria Elisabeth Street (University of Parma, Italy), the primary investigator of the LIFE-MILCH study, most EDCs detected are linked to diet and personal care products. Street noted that previous research has associated EDC exposure with neurodevelopmental problems, hormonal changes at birth, and altered growth patterns.

"Breastfeeding remains the recommended feeding method when possible," said Ryan Babadi, lead author of the Seattle study.

Ryan Babadi, lead author of the Seattle study and senior scientist at Toxic Free Future, stated that the findings raise concerns regarding infant development. Babadi also noted that breastfeeding remains the recommended feeding method when possible and that the results indicate a systemic issue with chemical regulation.

Policy Responses

The findings from the LIFE-MILCH study have prompted a prevention campaign in Italy, where several stakeholders have signed agreements to monitor and reduce these chemicals in their products. Researchers are recommending that public health officials develop strategies to reduce EDC exposure.