Greenwire: Prenatal exposures prompt EPA to re-examine chemical regulations.

U.S. EPA regulators convened with scientists last month to discuss how to design regulations for chemicals based on emerging science that connects exposures during pregnancy with disease much later in life.

A mother exchanges with her child in the womb chemicals that have remained constant for much of human evolution. They dictate which genes will be turned on and off in the child, which proteins the child will make in his body and how much of them.

New research, in a field called epigenetics, now suggests that these changes, made during the earliest part of gestation, could spell out the child’s longer-term medical record. It could determine his propensity for mood swings, his tendency to gain weight into the realms of obesity, his risk of developing cardiovascular disease or cancer when he hits 50, and his propensity of passing on his genes to his children.

The idea is that the child adapts to environmental cues in the womb that will reflect the chemical composition of the world, thus conferring a Darwinian fitness advantage.

The mix of chemicals a fetus is exposed to has exploded in the past 200 years, heralded by the Industrial Revolution. Technology has outstripped evolution, said Robert Chapin, senior research fellow in drug safety research and development at Pfizer Inc. People were suddenly surrounded by particulate matter from cars, coal-plant emissions, metals, organic molecules from hand sanitizers, body lotions and other chemicals, some of which could cross into the placenta and merge into the child’s aqueous world.

Some, such as folic acid, were intentionally given to moms as beneficial; others such as bisphenol A became common in the modern environment and had the ability to mimic hormones that are naturally present in humans. Yet others, such as arsenic and tin, are naturally present in some places.

Scientists now suspect that the altered chemical cues during the critical windows of pregnancy — at stages when gender is still developing and the human is little more than a collection of cells — could trigger pathways that manifest as disease well into adulthood.

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