New research has found a link between exposure during the first trimester of pregnancy to chemicals found in common consumer products and lower IQ in children by the age of 7.
For the study, scientists from the Icahn School of Medicine at Mount Sinai in the U.S. and Karlstad University in Sweden measured 26 chemicals in the blood and urine of 718 mothers during the first trimester of their pregnancies. Chemicals included bisphenol A (BPA), which is found in plastic food and drink containers, as well as pesticides, phthalates, and other chemicals found in consumer products.
Some of the 26 are known to disrupt hormone activity in humans, while others have been shown to do so only in animals, or are suspected of hormone disruption because they share chemical features with known disruptors, the researchers noted.
The researchers then followed up with the children at age 7 and found that those whose mothers had higher levels of the chemicals in their system during pregnancy had lower IQ scores — particularly boys, whose scores were lower by two points.
According to the study’s findings, bisphenol F (BPF), a BPA-replacement compound, made the highest contribution to lowering children’s IQ, suggesting that BPF is not any safer for children than BPA.
The study found that other chemicals of concern in the mixture were the pesticide chloropyrifos; polyfluoroalkyl substances, which are found in cleaning products; triclosan, a chemical found in antibacterial soaps; and phthalates, which are found in soft polyvinyl chloride plastics and cosmetics.
Many of the chemicals only stay in the body a short time, meaning that even a short-term exposure may be detrimental, according to researchers. This indicates that preventing exposure to these chemicals for pregnant women or women trying to become pregnant is critical to preventing neurological harm to children, they add.
“This study is significant because most studies evaluate one chemical at a time, however, humans are exposed to many chemicals at the same time, and multiple exposures may be harmful even when each individual chemical is at a low level,” said Eva Tanner, PhD, MPH, a postdoctoral researcher in the Department of Environmental Medicine and Public Health at the Icahn School of Medicine at Mount Sinai.
Some of these chemicals cross the placenta during pregnancy, exposing the fetus and potentially causing irreversible developmental damage, according to the scientists. While ending exposure to a short-lived pollutant may eliminate adverse effects in adults, exposure during critical periods of fetal development may be permanent, with subtle hormone changes potentially influencing health outcomes into adulthood, according to Tanner.
She adds the study only assessed exposure at a single time during early pregnancy, so more research needs to be done to understand how exposures throughout later pregnancy and childhood may influence the results.
The study was published in Environment International.
Source: Mount Sinai School of Medicine