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A Lesson We Keep Learning |
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Author: Bruce Lanphear, MD, MPH NOTE: This article was originally published on January 20, 2026 by Plagues, Pollution & Poverty on Substack. When the Data Doesn’t Fit the StoryI first learned that PFAS—the so-called forever chemicals—might interfere with breastfeeding from Megan Romano, then a post-doctoral student at Brown University. Romano was working with data from the HOME Study, a birth cohort in Cincinnati I designed to examine how early-life exposures shape children’s health. She was analyzing data on PFAS exposure and breastfeeding duration. When she showed me the results, I was stunned. After nearly twenty years studying breastfeeding with Cindy Howard, I’d never considered chemical exposure as a driver of breastfeeding duration—and the effect was too large to ignore. The mothers in the HOME Study had PFOA levels roughly twice the national average. The reason was painfully ordinary: their drinking water came from the Ohio River, and about 200 miles upstream sat DuPont’s Washington Works facility—the source of PFOA (C8) contamination that later became infamous. These women weren’t factory workers or living next to a hazardous waste site. They were drinking tap water. And Cincinnati, it turns out, wasn’t an outlier. A Pattern That Refuses to Go AwayA 2023 systematic review led by Timmerman summarized the evidence at the time: women with higher PFAS levels—especially PFOA—tended to breastfeed for shorter periods. The authors also highlighted an important complication. PFAS are excreted through breast milk, so women who had breastfed previously often had lower PFAS levels. That makes the science messier, but also more revealing. When researchers focused on first-time mothers, the pattern sharpened. Higher PFAS levels were consistently linked to shorter breastfeeding duration. Among women who had breastfed before, the association weakened—likely because earlier lactation had already reduced their PFAS burden. That pattern doesn’t undermine the evidence. It strengthens it. A Warning First Detected in the Lab
The pattern has since reappeared. In a recent New Hampshire study, Romano and her team found that women with higher PFAS levels—again, especially PFOA—breastfed for a shorter duration. The association was not subtle, and it persisted after accounting for factors that often cloud this kind of research. Different population. Different setting. Same result. “Breastfeeding isn’t a lifestyle choice. It’s a basic human function. If chemicals in our water and food are quietly eroding it, that isn’t a niche concern—it’s a warning.”At some point, repetition stops being coincidence and starts looking like a signal. And that is what unsettles me. Breastfeeding isn’t a lifestyle choice. It’s a basic human function. If chemicals in our water and food are quietly eroding it, that isn’t a niche concern. It’s a warning. Why Breastfeeding, of All Things?At first glance, breastfeeding might seem like an odd endpoint for toxicology. Biologically, it makes perfect sense—and we’ve seen this before, with DDT. Lactation isn’t a switch that flips on after delivery. It’s the culmination of mammary gland development that begins in utero, accelerates during puberty, and completes during pregnancy. It’s exquisitely hormone dependent. Estrogen, progesterone, prolactin, oxytocin—each must arrive on cue, in the right sequence. PFAS are hormone disruptors. They interfere with estrogen signaling, thyroid hormones, and lipid metabolism. They bind to receptors involved in mammary development. In laboratory studies, PFOS and PFOA disrupt mammary gland development. Exposed mice show impaired mammary differentiation and altered expression of milk proteins—changes that limit their ability to sustain normal lactation. Some struggle to adequately nurse their pups. The pups fail to thrive, not because the mothers lack motivation, but because the biology has been quietly rewired. Human studies now echo those findings. The strongest associations appear for exclusive breastfeeding, the period of highest physiological demand—consistent with impaired capacity rather than failure to initiate. This Isn’t About ChoiceWhen breastfeeding ends early, we’re quick to talk about personal choice, workplace barriers, or lack of support. Those factors matter. But PFAS complicates the story in an uncomfortable way. What if we’ve been blaming mothers for outcomes shaped decades earlier—not by willpower or choice, but by toxic chemicals that quietly interfered with mammary development and now sit in their water, food, and blood? Breastfeeding protects infants against respiratory infections, leukemia, and even death. For mothers, longer breastfeeding lowers the risk of breast cancer, ovarian cancer, and diabetes. Shortening breastfeeding doesn’t just affect infancy; it shapes health long after childhood. This isn’t a lifestyle issue. It’s a failure of chemical regulation. Not a One-Off—Not Even CloseThe Cincinnati story is often framed as a scandal—DuPont, C8, contaminated water. But focusing on scandal misses the larger truth. This is not an exception. It’s the rule. More than 170 million Americans—nearly half the population—have had PFAS detected in their drinking water. Globally, PFAS contamination has been documented on every continent, including Antarctica. These chemicals now fall with the rain. Once released, PFAS don’t politely degrade. PFOS and PFOA persist for years in the human body. PFNA persists even longer. And while industry has moved on to “replacement” PFAS, many share the same carbon-fluorine backbone that makes them stubbornly persistent and biologically active. What happened in Cincinnati is happening—quietly, unevenly, and persistently—across the world. What About the Next Generation?PFAS cross the placenta. They show up in cord blood. Exposure begins before birth and continues through childhood. If PFAS interfere with mammary development in adults, what happens when exposure occurs during fetal life or puberty—the windows when mammary tissue is being programmed? We don’t yet know. But history offers a warning. With DDT, diethylstilbesterol and lead, we learned too late that early exposures echo across a lifetime. PFAS may be teaching us the same lesson—slowly, quietly, and at enormous scale. A Question We Keep DodgingWe tend to ask narrow questions about PFAS: Which compounds are worst? What’s the safe dose? How low is low enough? The breastfeeding studies force a broader question: How many core human capacities are being subtly eroded by chemicals we never agreed to ingest?
The ability to
conceive. These aren’t fringe outcomes. They go to the core of human existence. “…industrial contamination doesn’t just cause disease—it reshapes biology.”PFAS are only one chapter in a long story. But they offer a stark illustration of how industrial contamination doesn’t just cause disease—it reshapes biology. The question isn’t whether this is happening. The question is how long we’re willing to pretend it isn’t. All of this leads to an unavoidable conclusion: PFAS cannot be regulated one chemical at a time. There are thousands of PFAS. Regulating them individually has become a regulatory shell game—ban one, replace it with a close cousin, declare progress. It’s a strategy that protects markets, not people. PFAS must be regulated as a class, and we need a concrete plan to drive exposures down—quickly and decisively—over the next five years. The targets are obvious. First, drinking water, the most direct and inequitable source of exposure, demands enforceable limits, rapid remediation, and accountability from polluters—especially near industrial sites and military bases. Second, industrial uses that contaminate air, soil, and wastewater must be eliminated at the source, rather than managed after communities are exposed. Third, consumer products with no essential function—stain-resistant clothing, grease-proof food packaging, cosmetics—should be phased out, not endlessly reformulated. This isn’t a call for perfection. It’s a call for prevention. What’s been missing isn’t evidence. It’s resolve. ■ To read more content like this please subscribe to Plagues, Pollution & Poverty on Substack. |
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