Scientists shatter old truths
about toxins and health

UPdate Summer 2007

Environmental reproductive health sounds like high fallutin’ language, but it lies at the heart of many people’s lives. It refers to the study of how pollutants in our environment may be interfering with people’s ability to conceive and give birth to a healthy child.

Reproductive health includes the fertility of both men and women and a woman’s ability to carry a pregnancy to term. It involves the quality and outcome of pregnancy, whether the baby is born healthy and whether he or she will grow into a healthy adult.

Scientists are finding that the effects of environmental pollutants on reproduction are far reaching. Some effects of environmental contaminants may be evident right away, such as low birth weight, pre-term birth and some birth defects, while others may not show up until adulthood. Scientists call the latter the fetal origins of adult disease.

Environmental reproductive health research is challenging some old scientific standards. The old standard of toxicity was “The dose makes the poison.” This assumed that only larger doses of chemicals would cause harm. Chemicals are presently regulated based on the notion that harm will only arise with exposures above a certain level.

Reproductive health science is developing strong evidence that there are four “critical windows of vulnerability” - conception, pregnancy, early childhood and adolescence. During these critical periods of development, tiny exposures to contaminants may have lifelong and intergenerational impacts. In some studies, low levels have been found to be more harmful than higher ones, turning old assumptions on their head. The very chemicals which may be most disruptive are often excluded from regulation, precisely because they are often used in smaller volumes than other hazardous chemicals.

Reproductive health research is also revealing a new twist on the debate as to whether disease is caused by “bad genes” or by environmental factors. New studies have revealed a frightening relationship between the two. Scientists have found that healthy genes can be damaged by environmental pollutants, and that this genetic damage can be passed on to the next generation and to all generations that follow.

These new insights add weight to arguments that we need to take precautionary action to reduce exposure to environmental pollutants which affect reproductive health.

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