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Study Examines How Pregnancy May Help the Body Eliminate Mercury from Fish

Monday, March 16, 2026

Researchers at the University of Rochester are investigating whether natural biological changes during pregnancy help reduce a fetus’s exposure to mercury. The project will examine how the maternal gut microbiome and pregnancy-related physiological changes may increase the body’s ability to eliminate methylmercury, the toxic form of mercury commonly found in fish, before it reaches the developing fetus.

“Much of environmental health research focuses on identifying risks,” said Matt Rand, PhD, associate professor of Environmental Medicine and the study’s principal investigator. “What excites us about this project is the opportunity to understand the body’s natural defenses. Namely, how pregnancy itself may help protect the fetus from environmental exposures like mercury.”

Building on decades of mercury research

Concern about prenatal mercury exposure has driven decades of research into how fish consumption affects fetal brain development. One of the most consequential efforts is the Seychelles Child Development Study, a landmark international research program that has followed families in the Seychelles for decades.

That work, led by scientists at the University of Rochester, has found no measurable harm to children’s neurodevelopment in a population that consumes roughly ten times more fish than in the United States. These and other findings have helped shift public-health guidance toward encouraging pregnant people to eat fish to obtain key nutrients important for fetal brain development.

Still, questions remain about how the body manages mercury exposure during pregnancy.