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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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From Harvard Gazette:

Exposure in the womb to bisphenol A (BPA) — a chemical used to make plastic containers and other consumer goods — is associated with behavior and emotional problems in young girls, according to a study led by researchers at Harvard School of Public Health (HSPH), Cincinnati Children’s Hospital Medical Center, and Simon Fraser University in Vancouver, British Columbia.

BPA is found in many consumer products, including canned food linings, polycarbonate plastics, dental sealants, and some receipts made from thermal paper. Most people living in industrialized nations are exposed to BPA. BPA has been shown to interfere with normal development in animals and has been linked with cardiovascular disease and diabetes in people. In a 2009 study, HSPH researchers showed that drinking from polycarbonate bottles increased the level of urinary BPA.

In this study, published Oct. 24 in an advance online edition of Pediatrics, lead author Joe Braun, research fellow in environmental health at HSPH, and his colleagues found that gestational BPA exposure was associated with more behavioral problems at age 3, especially in girls.

The researchers collected data from 244 mothers and their 3-year-old children in the Health Outcomes and Measures of the Environment Study, conducted in the Cincinnati area. Mothers provided three urine samples during pregnancy and at birth that were tested for BPA; their children were tested each year from ages 1 to 3. When the children were 3 years old, the mothers completed surveys about their children’s behavior.

“None of the children had clinically abnormal behavior, but some children had more behavior problems than others. Thus, we examined the relationship between the mom’s and children’s BPA concentrations and the different behaviors,” Braun said.

BPA was detected in more than 85 percent of the urine samples from the mothers and more than 96 percent of the children’s urine samples. The researchers found that maternal BPA concentrations were similar between the first sample and birth. The children’s BPA levels decreased from ages 1 to 3, but were higher and more variable than that of their mothers.

After adjusting for possible contributing factors, increasing gestational BPA concentrations were associated with more hyperactive, aggressive, anxious, and depressed behavior, and poorer emotional control and inhibition in the girls. This relationship was not seen in the boys.

The study confirms two prior studies showing that exposure to BPA in the womb impacts child behavior, but is the first to show that in utero exposures are more important than exposures during childhood, Braun said.

“Gestational, but not childhood BPA exposures, may impact neurobehavioral function, and girls appear to be more sensitive to BPA than boys,” he said.

Although more research is needed to fully understand the health effects of BPA exposure, clinicians can advise those concerned to reduce their BPA exposure by avoiding canned and packaged foods, thermal paper sales receipts, and polycarbonate bottles with the number 7 recycling symbol, the authors wrote.

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