Headline overstates but article correctly highlights hidden consequence of pesticide exposure.

Terri Hansen’s article, “Pesticide exposure deprives Yaqui girls of breastfeeding - ever” published in Indian Country Today, tackles an issue that has received very little attention to date: how lactation may be impacted by environmental chemicals such as pesticides. In her article, she integrates this new line of research into the larger body of work on endocrine disrupting chemicals and their role in the origin of a wide spectrum of health abnormalities. 

The article focuses on a “natural experiment” in which a Mexican Yaqui valley community adopted pesticide use in the 1950s, while the closely-related, neighboring foothill community stuck to traditional farming methods.  Anthropologist Elizabeth Guillette has studied health outcomes in the two communities for decades, uncovering a suite of health concerns in those who were exposed to the pesticides.   

Among her findings was the discovery that relative to their overall breast size, girls – ages 8-10 that were approaching puberty – from the valley community had impaired mammary gland development, with nearly 20 percent showing no mammary tissue whatsoever.  This was in contrast to the foothill community, in which breast size and mammary tissue development were closely linked, as is typically found in development. 

Contrary to the article's headline, the researchers did not directly assess breastfeeding or ability to breastfeed in the Yaqui, so it is a stretch at this point to make the claim that the girls will never be able to breastfeed their children. The reporter should have included comments from scientists or doctors about the expected effects on the girls' breastfeeding ability. We are left wondering if experts, including Guillette, would back up the headline's claim.

Given that mammary tissue is necessary for lactation, it is reasonable to predict that follow-up research may show that girls in the exposed community may have difficulty breastfeeding later in life. Animal research already supports that direction. One of the few existing studies on the topic echoes Guillette’s results in the Yaqui, finding that mice prenatally exposed to the endocrine disruptor dioxin also show impaired mammary development and milk production. 

Hansen also explains that pesticides can act as endocrine disruptors, altering the normal action of reproductive hormones in the body. Many endocrine disruptors have been identified and are being studied. But, much of the focus has been on fertility, cancer risk, and neurodevelopment, leaving other concerns like lactation relatively unexamined.  

Hansen deftly broaches the political implications of the new findings as well, namely that this is further evidence of the lack of protections afforded indigenous peoples, particularly farming communities.  Yet it is important to note that this is a more systemic problem, not solely limited to those in particular occupations or populations. 

All of us are exposed to endocrine disruptors on a daily basis. Research studies like this one – and the media articles that explain them – highlight the fact that we are still learning the extent of their effects, particularly on pregnant women and children.