As with many toxins, exposure to the toxic metal cadmium while pregnant can adversely impact fetal development. Now, researchers on the Rutgers School of Public Health think they’re starting to know how the metal inflicts its damage: by disrupting placental hormones that regulate pregnancy physiology.

Unlike other toxins, relatively little cadmium crosses the placenta to directly impact the fetus. As an alternative, the placenta concentrates cadmium in its tissue at rates of as much as six times that present in umbilical cord serum.

“We already know rather a lot about cadmium and its detrimental impacts on fetal health, corresponding to low birthweight,” said Zorimar Rivera-Núñez, an assistant professor within the Department of Biostatistics and Epidemiology and lead writer of the study published within the journal Toxics. “What we do not really understand is how the placenta regulates exposure to cadmium and other toxicants. That is what this research was trying to establish.”

Only a few epidemiological studies have examined cadmium’s endocrine-disrupting potential while pregnant, the researchers said. To handle this data gap, Rivera-Núñez, along with Megan Hansel, a doctoral degree student on the Rutgers School of Public Health, and Camila Capurro, a clinical research assistant at the varsity and an MPH student, analyzed urine samples from 294 pregnant women who participated within the Understanding Pregnancy Signals and Infant Development (UPSIDE) study in Rochester, N.Y.

Study participants provided urine samples during each trimester and answered questions on demographics, lifestyle, health history and other measures.

By testing their urine for cadmium and sex steroid levels, including testosterone, which is very important to fetal brain development, the researchers determined as cadmium levels increased, levels of free testosterone – testosterone that won’t attached to a protein – decreased.

At the identical time, total testosterone – each free and certain testosterone – remained stable, suggesting cadmium may influence fetal exposure to sex steroids, which in turn can adversely influence fetal growth.

“We expect that what cadmium is doing is altering the certain/unbound technique of testosterone while pregnant,” said Rivera-Núñez. “If cadmium is interfering with these binding proteins, it would explain why we’re seeing lower levels of free, or unbound, testosterone.”

Rivera-Núñez said one goal of this research is to assist pregnant women avoid cadmium exposure. Doing so might be difficult: Although human exposure occurs through tobacco products, it’s often present in foods, accumulating within the environment through industrial emissions, mining and the burning of coal. To handle these sources, expectant moms need to know the risks and regulators must work to maintain the toxin from the environment in the primary place, she said.

“If we are able to understand the mechanisms by which cadmium impacts growth in utero, we would give you the option to know how similar chemicals work on the placenta,” Rivera-Núñez said. “Eventually, that might help lower exposure risks across the board.”

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Journal reference:

DOI: 10.3390/toxics11070589