Early DEHP exposure raises anxiety in male rats, study finds

A common plastic additive linked to everyday products showed a lasting behavioral effect in male rats when exposure happened before birth and continued through nursing. In the study highlighted by the Endocrine Society, the animals later showed more anxiety in a standard test, a result that sharpens the question of how seriously regulators should weigh early-life exposure to DEHP.

Osvaldo Juan Ponzo, a physiology professor at the University of Buenos Aires School of Medicine in Buenos Aires, Argentina, led the work. Pregnant female rats received DEHP orally every day from the first day of gestation until their litters were weaned. When the male pups reached 70 days old, the researchers placed them in an elevated plus maze, a common anxiety test that measures how much time animals spend in open versus enclosed spaces.

The DEHP-only group spent less time in the open arms, more time in the closed arms, and froze more often than the comparison animals. The team also tested whether GABA agonists or testosterone would change the behavior, a design that points to possible involvement of GABAergic signaling and testosterone regulation. The pattern suggests that timing may matter as much as dose, and that the effects may differ by sex.

The chemical at issue is DEHP, a phthalate plasticizer used in medical devices, toys, shower curtains and raincoats. The finding does not mean that every person exposed to plastics will develop anxiety, but it does add to a larger body of concern about endocrine-disrupting chemicals, which can interfere with hormones and neurodevelopment during critical windows of development.

That warning remains tempered by the limits of the evidence. A Science Media Centre expert reaction described the abstract as unpublished conference material and said the findings should be tested in humans before conclusions are drawn about offspring anxiety. Jean Golding also said cohort studies with stored maternal blood samples could help determine whether maternal phthalate exposure is tied to child anxiety.

The federal backdrop is also changing. The U.S. Environmental Protection Agency reported that the median level of DEHP metabolites in children’s urine fell from 57 micrograms per liter in 2001-2002 to 13 micrograms per liter in 2017-2018, while the Centers for Disease Control and Prevention continues to track phthalates through its National Biomonitoring Program. EPA’s December 2025 non-cancer human health hazard assessment for DEHP shows the chemical remains under active review, even as it stays embedded in products that millions of Americans encounter every day.