Summary: New animal research suggests that perfluorohexanoic acid (PFHxA), a short-chain member of the PFAS family often considered a safer alternative, can produce lasting behavioral changes when exposure occurs during early development. In a rodent model, male mice exposed to PFHxA before birth and through lactation showed increased anxiety-like behavior, memory impairments, and reduced activity levels into adulthood.
These effects were sex-specific: female mice exposed to the same regimen did not display the same behavioral changes. The male-focused outcomes echo the sex bias seen in certain human neurodevelopmental disorders such as autism spectrum disorder and ADHD, and raise questions about the assumption that short-chain PFAS are benign.
Key Facts:
- Male-specific outcomes: Only male mice showed measurable anxiety, memory deficits, and lower locomotor activity following developmental PFHxA exposure.
- Enduring effects: Behavioral changes persisted into adulthood, long after PFHxA levels in brain tissue returned to control levels.
- Regulatory relevance: Findings challenge the safety profile attributed to short-chain PFAS and support the need for stricter evaluation and potential regulation.
Source: University of Rochester
Background: Per- and polyfluoroalkyl substances (PFAS), often called “forever chemicals,” have been used for decades in a wide range of industrial and consumer products because of their resistance to heat, stains, oil, and water. Their persistence in the environment and in human tissue has led to growing public health concern. PFHxA is a shorter-chain PFAS increasingly used as an alternative to longer-chain compounds that have been phased out or restricted.
Researchers at the Del Monte Institute for Neuroscience, University of Rochester, conducted a study to determine whether developmental exposure to PFHxA affects behavior in mammals. The research, published in the European Journal of Neuroscience, evaluated behavior in adult offspring after mothers received PFHxA during pregnancy and nursing.
Ania Majewska, PhD, professor of Neuroscience and the study’s senior author, noted that the male-specific behavioral effects mirror the sex bias seen in several neurodevelopmental disorders. The study’s lead author, Elizabeth Plunk, PhD (’25), emphasized that while the observed changes were mild, the persistence of these effects into adulthood is concerning, particularly because PFHxA is often presented as a safer alternative to legacy PFAS.
Experimental exposure was delivered to pregnant mouse dams through a treated food item during gestation and lactation. Two exposure levels were tested: a lower dose (0.32 mg/kg body weight) and a higher dose (50 mg/kg body weight). Investigators measured PFHxA concentrations in brain tissue at several time points (postnatal day 1, day 21, and day 90). The higher dose produced measurable increases in brain PFHxA at early time points, and both doses showed elevations at P21; by P90, PFHxA concentrations had returned to levels comparable to controls.
Behavioral testing in adulthood revealed male-specific differences in multiple domains. Male mice exposed developmentally to higher PFHxA levels showed reduced exploratory activity, heightened anxiety-like behavior, and impairments in novel object recognition, a test of memory. Motor strength and gait measures (hang test, inverted screen test, and gait scan) did not show overt deficits, suggesting the effects were selective for emotional and memory-related behaviors rather than global motor dysfunction. Female offspring did not exhibit these behavioral changes under the same exposure conditions.
The authors underline that these are preliminary findings in a mammalian model and call for broader investigation. Future work should explore cell-type specific and molecular mechanisms in brain regions implicated in motor control, fear and anxiety, and memory processing. Understanding how PFHxA interacts with neural circuits during critical windows of development will be important to determine risk and inform safety assessments.
Despite its shorter fluorinated chain, PFHxA has demonstrated environmental persistence. The European Union imposed restrictions on PFHxA in 2024, reflecting mounting regulatory scrutiny of both legacy and next-generation PFAS. In the United States, regulatory agencies have begun setting limits for PFAS in drinking water, a step intended to reduce exposure for large populations.
PFAS exposure has been linked to a range of human health outcomes, including developmental effects in infants and certain cancers. The new study adds developmental neurobehavioral concerns to that list for PFHxA and stresses the importance of including neurotoxicity endpoints in safety evaluations for short-chain PFAS.
Additional contributors to the study include Marissa Sobolewski, PhD (University of Rochester Medical Center); Katherine Manz, PhD (University of Michigan); and Andre Gomes and Kurt Pennel, PhD (Brown University). The research received funding from the National Institutes of Health, the University of Rochester Intellectual and Developmental Disabilities Research Center, and the University of Rochester Environmental Health Services Center.
About this neurodevelopment research news
Author: Kelsie Smith Hayduk
Source: University of Rochester
Contact: Kelsie Smith Hayduk – University of Rochester
Image: Image credited to Neuroscience News
Original Research: Open access. “Gestational and Lactational Exposure to Perfluorohexanoic Acid Affects Behavior in Adult Male Mice: A Preliminary Study” by Ania Majewska et al., European Journal of Neuroscience
Abstract
Gestational and Lactational Exposure to Perfluorohexanoic Acid Affects Behavior in Adult Male Mice: A Preliminary Study
Legacy PFAS have been associated with increased risk for male-biased neurobehavioral disorders. Industries have phased many legacy compounds out and introduced next-generation PFAS such as PFHxA. While zebrafish studies suggest developmental effects of PFHxA on activity, developmental neurotoxicology data in mammals have been limited. Human biomonitoring shows PFHxA in the serum of pregnant women and in breast milk, and postmortem work indicates PFHxA reaches the brain with elevated levels in the cerebellum. Based on these observations, researchers predicted potential motor and behavioral impacts from developmental exposure.
To test this, pregnant C57BL/6J mice received daily doses of vehicle (water), a low dose of PFHxA (0.32 mg/kg body weight), or a high dose (50 mg/kg body weight) from gestational day 0 through postnatal day 21. Brain PFHxA increased at early time points in exposed groups but returned to control levels by postnatal day 90. Behavioral testing in adulthood detected male-specific alterations in the open-field test, elevated plus maze, and novel object recognition, while gross motor tests such as the hang test, inverted screen, and gait scan showed no clear deficits. These preliminary data suggest that developmental PFHxA exposure can produce long-lasting behavioral changes in a mammalian model and underscore the need for expanded cognitive and mechanistic evaluations.