A Doctor’s Viewpoint: The Womb Cannot Protect Against Many Toxins

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A Doctor’s Viewpoint: The Womb Cannot Protect Against Many Toxins

by Dr. Maida P. Galvez

With Permission from Mount Sinai School of Medicine, Center for Children’s Environmental Health and Disease Prevention Research

Thursday, April 26, 2007

“A little kid goes from a single cell to a laughing, sociable, intelligent, friendly human being over a course of two years; that’s dramatic growth and development,” stated Ken Olden, Director of the National Institute of Environmental Health Sciences. The baby in the womb is at a critical window of vulnerability.

. In the nine months of gestation the human body undergoes its most rapid growth, making it especially susceptible to environmental toxins. At any stage in a baby’s growth environmental exposures such as outdoor air pollution, lead, mercury, polychlorinated biphenyls, and pesticides may alter the normal development of the brain, heart and lungs.

Several environmental toxins readily cross the placenta, which is the primary source of nutrients for the baby. These toxins include lead, mercury, carbon monoxide and polyaromatic hydrocarbons (PAHs). PAHs are products of combustion from sources that include cigarette smoke and diesel exhaust. It is through the placental circulation that toxins may enter into the babies’ blood supply and are distributed throughout the developing organ systems.

The developing brain with its complex network of connections is at greater risk to toxic insults than the fully developed adult brain. Neurotoxins have the ability to interfere with several stages of central nervous system maturation including individual brain cell growth, closure of the spinal cord, and the formation of the countless interconnections of the nervous system throughout the body. As neurotoxins such as lead and mercury enter the babies’ blood supply, they can affect the specificity of the brain’s network of connections, permanently altering a child’s intelligence and development.

While environmental toxins in the mother’s blood stream may result in no apparent clinical effects in the mother, there may be long-lasting effects to the baby. Compared to the mother’s dose of exposure, the developing infant is exposed to greater quantities of environmental chemicals per pound of body weight. This is compounded by the fact that developing babies have immature immune and metabolic systems, which may make the baby less able to detoxify harmful chemicals.

The unique vulnerability of the developing baby in utero is well illustrated historically in Iraq in the 1950’s and 60’s when mercury treated seed grain originally intended for crops was instead consumed by peasants. While pregnant women exposed to methyl mercury had relatively few clinical side effects many of their children developed very severe abnormalities. Infants exposed in the womb were found to have small head sizes (microcephaly), irritability, abnormal reflexes and cerebral palsy. In contrast, pregnant mothers often experienced only mild symptoms of mercury toxicity.

Rigorous research in the area of children’s environmental health is actively examining the question of how environmental toxins impact the growth and development of children from conception to adulthood. It is now widely recognized that the baby in utero is uniquely susceptible to a variety of exposures. Links have been made between outdoor air pollutants and sudden infant death syndrome, cigarette smoke and pre-term birth, pesticides and impaired growth, and between polychlorinated biphenyls and behavioral problems to name a few.

Existing safety thresholds do not adequately account for babies’ and children’s unique vulnerabilities. Regulations do not exist requiring pre-market testing to ensure that products have no long term effects such as developmental delays, decreased intelligence, behavioral problems, disruption of the endocrine system or on the development of childhood or adult onset cancers. Much remains to be known about how everyday exposures to pesticides, plasticizers, flame retardants, and many other environmental toxins impact the health of children and babies in utero.

Until these standards exist, there are simple things parents can do to minimize these exposures.This includes checking for lead hazards prior to home renovations and hiring certified contractors if needed to conduct an abatement, choosing integrated pest management techniques for pest control over fumigation or sprays, and limiting the amount of fish consumption during pregnancy to an average of one serving (four to six ounces) per week in order to minimize mercury and PCB exposure.

Expectant parents often make lifestyle changes to ensure the healthy development of their child, from abstaining from alcohol and avoiding cigarette smoke, to making renovations in the home in order to prepare for the babies arrival. As the state of children’s environmental health research progresses, it is prudent for parents to exercise caution and minimize potential toxic environmental exposures in the home, day care, school, work setting and the community at large.