Studies detect endocrine-disrupting chemicals in breast milk samples

Two studies released this month examined breast milk samples from hundreds of mothers in Italy and the United States and reported the presence of several chemicals known to affect hormone function. In the Italian study, researchers collected breast milk and urine from 336 mothers and infants at one, three, and six months after birth.

They tested for more than 50 substances and detected bisphenol A in roughly half the milk samples, bisphenol S at rising levels over time, and phthalates in more than 90 percent of samples taken one month after birth. Polycyclic aromatic hydrocarbons appeared in infant urine but rarely in milk.

Parabens and the herbicide glufosinate were also found in both mothers and babies, with concentrations in infants increasing as they aged. A separate study in Seattle tested milk from 50 mothers and found at least one endocrine-disrupting chemical in 92 percent of samples.

Those samples had previously shown PFAS compounds and flame retardants.

Study context and recommendations The authors stated that some detected levels fell below World Health Organization safety thresholds yet remained within ranges linked in earlier research to possible health effects. They noted that infancy is a period when exposure effects may be magnified.

Both research teams said their results are not intended to discourage breastfeeding. They called for stronger measures to reduce environmental contamination from plastics, preservatives, and agricultural chemicals. More than 3.5 million women give birth in the United States each year, and government data show that about 84 percent begin breastfeeding.