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Presentation Notes: Pesticides are chemicals intended to kill, repel, or attract (in order to kill) unwanted organisms., Pesticides are used widely throughout the world, especially in agriculture to protect crops and in commercial greenhouses and nurseries.,,

Presentation Notes: More than 1.2 billion pounds of pesticides are used in the United States each year., Commercial agriculture accounts for more than three-quarters of all pesticide use. Industrial, commercial, and government use, combined with household use, accounts for the remainder in roughly equal proportions.,,

Presentation Notes: According to a recent survey, 75 percent of U.S. households used at least one pesticide product indoors during the past year., Reasons for use may be:, To eliminate insect or rodent infestations, For lawn and garden care, On domestic pets to eliminate and prevent fleas, In addition to chemical pesticides, there are also biopesticides, which are derived from natural materials (e.g., so-called beneficial insects and bacteria). This unit addresses only chemical or chemically derived pesticides., This course provides the reproductive health professional with basic knowledge about the reproductive-related effects of the more commonly encountered pesticides.,,

Presentation Notes: Chemical pesticides have been used in the United States for most of the 20th century., [CLICK], One of the best-known chemical pesticides is DDT, which was developed in 1874., [CLICK], Its properties as a pesticide were discovered in the 1930s., [CLICK], In World War II it was used to combat typhus., [CLICK], In the 1940s, it became available as a pesticide in agriculture., [CLICK], In 1962, Rachel Carson published Silent Spring, which publicized the adverse environmental effects of DDT on birds and wildlife. This book was a seminal influence on the environmental movement., [CLICK], DDT was banned in the United States and in many other places in the world in 1972.,,

Presentation Notes: Rachel Carson’s book Silent Spring first brought to public attention the adverse consequences of widespread use of DDT for humans, animals, and the environment., Since then, new knowledge has emerged about the effects of pesticides, not only during pregnancy but also on both male and female gametes before fertilization and conception., Since DDT was banned in the 1970s, there has been a move toward less environmentally persistent chemicals in general.,

Presentation Notes: Pesticides can be classified by the type of organism they target or by chemical class., Some classes of pesticides are used to target more than one type of organism (e.g., organophosphates are mostly used as insecticides, but some are also used as rodenticides).,

Presentation Notes: Most common sources of pesticide exposure:, Residues on food. In a recent survey, the US Department of Agriculture (USDA) found that 64% of sampled fresh fruit and vegetables and 59% of processed fruit and vegetables had detectable pesticide residues., Tap water that contains small amounts of pesticides (e.g., from nearby agricultural runoff or seepage into groundwater), Area-wide insecticide or herbicide applications, Occupational exposures (e.g., pesticide applicators, fruit and vegetable harvesters, farm and industrial workers),

Presentation Notes: Household use of insecticides, rodent traps, herbicides, or pet flea products are sources of pesticide exposure.,

Presentation Notes: Contaminated dust from any of these products—this is an especially important source of exposure for children, Pets tracking pesticides into the home from the outdoors after coming in contact with pesticide-treated areas, Use of mosquito and other insect repellents, Use of herbal medications in plant or seed form,

Presentation Notes: Pesticides are formulated from both “active” and “inert” ingredients., The more than 1,300 active ingredients in pesticides have different structures, toxicities, and mechanisms of action., “Inert” does not mean “benign” or “harmless,” however.,

Presentation Notes: The term “inert” is not a measure of health risk, but a functional designation., Inert ingredients are included in the chemical composition of pesticides to, for example, increase their efficacy or facilitate their delivery., Some of these ingredients may actually increase the toxicity of the pesticide to which they are added.,

Presentation Notes: Pesticides can enter the body through inhalation, oral ingestion, or skin exposure. During pregnancy, the fetus can be exposed in the uterus.,

Presentation Notes: For at least some pesticides,, [CLICK], Pesticides may be present in water, air, soil, or food., [CLICK], Pesticides can enter the body through inhalation, ingestion, or skin contact., This is the point of biologic uptake, or exposure., [CLICK], They then can travel to a target organ, such as the testes or ovaries, where…, [CLICK], …they affect biological processes…, …which leads to a clinical effect.,

Presentation Notes: Pesticides and their metabolites have been found in men, women, and neonates throughout the world.,

Presentation Notes: Pesticide exposure is ubiquitous, especially in the Northern hemisphere.,

Presentation Notes: Because it is not ethically feasible to conduct prospective, randomized clinical trials on the effects of pesticide exposure in humans, most of the data that we do have come from animal studies and epidemiological observations., There is a large body of work in this area, but opinions are divided as to the extent that the results can be applied to humans.,

Presentation Notes: Environmental exposures to toxicants such as pesticides can affect people at all life stages, including before birth and during childhood, adolescence, and adulthood. These exposures can have direct effects at all stages of life, not just during pregnancy., Exposures can influence the ability to conceive and can affect fetal/child development., The effects of environmental exposures can emerge when a couple tries to conceive,, [CLICK], during pregnancy, once conception has occurred,, [CLICK], during the development of the embryo and fetus,, [CLICK], in the newborn after birth,, [CLICK], or later in life—including that baby’s personal health and eventual fertility as an adult., An online tool called “Critical Windows of Development” is available from The Endocrine Disruption Exchange (TEDX). It provides a timeline of human embryonic/fetal development, along with animal research on low-dose exposure to endocrine-disrupting chemicals (EDCs) during development and altered health outcomes. More information about this online tool will be provided at the end of this presentation.,

Presentation Notes: Exposure to environmental toxins during certain critical periods of development have been found to be associated with reproductive-related effects in both animals and humans.,,

Presentation Notes: In women, pesticide exposure may affect reproductive processes and outcomes through several mechanisms:, Direct damage to cell structure, Interference with cell function, Biotransformation that results in toxic metabolites, A number of adverse reproductive outcomes have been linked to pesticide exposure.,

Presentation Notes: Potential reproductive effects of pesticides in men include testicular damage, which may result in genetic alterations to sperm and reduced fertility., Other effects include altered hormonal function.,,,

Presentation Notes: DBCP, or 1,2-dibromo-3-chloropropane, was once widely used as a pesticide in soil by the US agriculture industry., Its agricultural use was halted in the United States by the late 1970s to the mid-1980s., Small amounts are still produced as an ingredient in flame retardants., Long-term exposure has been linked to male reproductive effects, including lower sperm counts, altered sex ratio (to female births), and infertility.,

Presentation Notes: Organophosphates were originally used as pesticides in the 1930s and were later developed by the German military in chemical warfare during World War II., These chemicals disrupts the cholinergic nervous system by inhibiting cholinesterase, producing paralysis and death., Organophosphates are still widely used in lawn and garden treatments.,

Presentation Notes: Pyrethroids are synthetic versions of chemicals called pyrethrins, which occur naturally in chrysanthemum flowers., Pyrethroids are common in household pesticides as well as in commercial agriculture., Thousands of pyrethroids have been developed, but fewer than a dozen are used in the U.S.,

Presentation Notes: Some recent research on environmental reproductive effects has focused on a group of chemicals known as endocrine-disrupting chemicals, or EDCs., EDCs are chemicals that interfere with hormonal synthesis, metabolism, function, carrier protein levels, and other mechanisms.,

Presentation Notes: Unlike obvious physical birth defects, the effects of pesticides on development may not be evident at birth but may manifest later in life., Preconception, prenatal, and postnatal (via lactation) exposure of both women and men to pesticides has been found to be associated with adverse reproductive outcome in their offspring:, Childhood and adult cancer, Delayed developmental milestones, New-onset childhood asthma, Childhood lung and middle-ear infections, allergies, and effects on postnatal growth,

Presentation Notes: This table summarizes some of the evidence in humans of the reproduction-related effects of pesticide exposure., These results were based on several epidemiologic studies finding fairly consistent associations and evidence of exposure-risk relationships after controlling for potential confounding factors.,

Presentation Notes: The question of what to do about environmental exposures is a difficult one for a number of reasons:, Because experiments cannot be carried out in humans for ethical reasons, most of the current scientific knowledge of environmental exposures is based on studies in animals, the results of which cannot always be easily or directly extrapolated to people., That said, there is enough reliable evidence to suggest that some guidance can be offered to patients to avoid or at least limit their exposures where this is practical., Each patient must be considered individually on the basis of his or her particular environmental and personal circumstances and factors., Finally, although some degree of exposure to environmental toxicants is unavoidable, specific changes can and do make a difference.,

Presentation Notes: Patient counseling should focus on critical windows of susceptibility for all patients.,

Presentation Notes: An environmental history should be incorporated into reproductive health histories of both women and men to determine whether there are potentially harmful exposures and to help guide patients in making decisions., This is especially important at vulnerable stages such as early childhood, puberty, adolescence, preconception planning, and pregnancy.,

Presentation Notes: CH2OPS is a helpful memory aid to review the various domains of life in which environmental exposures occur., The CH2OPS domains can be used in the environmental history to ask about a patient’s environmental exposures, as well as to educate and raise awareness about potential harmful exposures., Within each of these domains, clinicians can help guide patients by learning about, and making patients aware of, resources and alternatives in their communities, homes, and personal lives that can help them to minimize their exposure to toxicants., After each of the next several slides, which give examples of where toxicants can be found within each domain, are examples of such resources and alternatives.,

Presentation Notes: Sources of exposures to environmental toxicants in the community may exist in urban, suburban, and rural environments., These are some examples of sources of environmental toxicants that may exist in a community’s air, water, and soil.,

Presentation Notes: Patients can be counseled to take some practical steps like these to reduce their exposure to environmental toxicants at the community level., There are probably environmental public health groups and resources in your communities that will be able to provide this type of information for your patients.

Presentation Notes: Commonly used chemicals in the home also may be a source of environmental toxicants., Exposure to toxicants may occur through the use of, for example, paints, glues, and solvents; household cleaning products; and automobile care products., Recreational fishing or water sports may increase the risk of exposure to mercury and other contaminants.

Presentation Notes: Recreational fishing or water sports may increase the risk of exposure to mercury and other contaminants.

Presentation Notes: Some practical things can be done to reduce or eliminate environmental exposures in the home.

Presentation Notes: Buy organic when possible. If you can’t buy organic, choose the products that have been shown to contain less pesticides.

Presentation Notes: Read labels on cleaning products to be aware of their contents or make your own nontoxic cleaning products with everyday ingredients.

Presentation Notes: The US Food and Drug Administration (FDA) advises children and pregnant women to avoid eating shark, swordfish, king mackerel, and tilefish, which have the highest potential for mercury contamination., Local advisories should be checked for information about the safety of fish caught in local waters

Presentation Notes: Some practical things can be done to reduce or eliminate environmental exposures when participating in hobbies.

Presentation Notes: Work exposures include exposure to chemicals, radiation, biological agents, pesticides, and other toxicants., Exposure can occur in all types of occupations, including skilled and unskilled labor, office work, and others.

Presentation Notes: Some practical things can be done to reduce or eliminate environmental exposures in the workplace.

Presentation Notes: Some practical things can be done to reduce or eliminate environmental exposures in schools.

Presentation Notes: Personal habits, including diet and consumption of alcohol, tobacco products, and medications; and use of personal care products are another potential source of exposure.

Presentation Notes: Some practical things that can be done to reduce or eliminate environmental exposures in the Personal domain.

Presentation Notes: Low socioeconomic status may increase the risk of exposure to environmental toxicants in communities and neighborhoods.

Presentation Notes: Some practical things can be done to reduce or eliminate environmental exposures in the Socioeconomic domain.

Presentation Notes: Talking Points:, When talking to both male and female patients, remember that identifying and reducing exposures to potentially harmful toxicants now increases the likelihood of a successful pregnancy outcome.

Presentation Notes: The ARHP Web site provides information on environmental and reproductive health, including news articles, continuing education, research, and patient resources.,

Presentation Notes: These are some resources to help guide patients’ decision-making., In addition, most universities have occupational health clinics staffed by physicians with expertise in occupational and environmental medicine., A number of states have pesticide poisoning surveillance programs (see http://www.cdc.gov/niosh/topics/pesticides/Statebase.html for a list).,

Presentation Notes: A number of resources for clinicians are available to educate and raise awareness, which will aid in patient counseling., “Critical Windows of Development” is an online tool provided by The Endocrine Disruption Exchange (TEDX). It shows a timeline of human embryonic/fetal development, together with animal research on exposure to low-dose EDCs and altered health outcomes., ReproTox is an online database for providers and consumers that presents information on more than 5,000 agents and exposures and their reproduction-related effects., TOXNET contains online databases on toxicology, hazardous chemicals, environmental health, and toxic releases.,

Presentation Notes: Occupational and environmental health departments in universities are a reliable source of information on environmental health., The American College of Occupational and Environmental Medicine is a membership organization for physicians who specialize in the environmental health and safety of workers, workplaces, and environments. Resources for clinicians are available on its Web site., Hosted by the University of Maryland School of Nursing, EnviRN provides scientific information on environmental health and nursing. Its Databases and Assessment Tools page provides a wealth of information on health effects on humans of environmental exposures, summaries on selected chemicals and sources of potential exposure, Toxicity and Exposure Assessment for Children’s Health (TEACH), access to National Library of Medicine databases, and more.,

Presentation Notes: The body of scientific evidence continues to build about the impact of pesticides on the reproductive health of both women and men., A precautionary approach emphasizing prevention provides for good patient and public health., Guidance on preventing patient exposures to pesticides should be incorporated into health care for patients who may become pregnant in the near or distant future.,

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Presentation Notes: Over the past several decades, there has been an increasing awareness of how exposure to certain manufactured substances in the environment can affect human health in general:, Air pollution from motor vehicles, industrial plants, commercial businesses, etc. Water pollution from wastewater, industrial accidents, acid rain, agricultural runoff, etc. Harmful effects from building materials (e.g. asbestos, lead-based paint), Chemicals and metals in food (e.g. pesticides used on produce, hormones and antibiotics added to animal feed, mercury in fish), Substances in personal care products (e.g. shampoo, sunscreen, lipstick), This curriculum focuses primarily on the reproduction-related effects of exposure to chemicals and heavy metals. Other significant environmental agents include:, Physical agents, such as radiation, Biological agents, Nutrition, Socioeconomic factors

Presentation Notes: During the same period, scientists have also begun to understand that environmental exposures can specifically affect reproductive health and human development.

Presentation Notes: A number of recently identified trends in fertility and reproduction have raised concerns for scientists, clinicians, and patients. Some of these observations have been seen only in certain geographic areas, and some of them are more widespread:, A rising incidence of testicular cancer—the rate is approaching 1% in some parts of Europe (Bray et al. 2006), Low average sperm counts in European males—approximately 20% of young men from Norway and Denmark were found to have sperm concentrations lower than the World Health Organization reference level of 20 x 106 spermatozoa/mL, and approximately 40% had <40 x 106 spermatozoa/mL, which may be the threshold below which fertility is impaired (Jørgensen et al. 2006), Indications of an annual decline of ~1% in serum testosterone in males for the past 40–50 years (Travison et al. 2007)

Presentation Notes: A number of recently identified trends in fertility and reproduction have raised concerns for scientists, clinicians, and patients. Some of these observations have been seen only in certain geographic areas, and some of them are more widespread:, Decline in age of pubertal development in girls (and possibly boys) over the past 30 years (Euling et al. 2008, Herman-Giddens et al. 2006), Decline in ratio of male to female births in some populations. Some populations have no boys being born (Hertz-Picciotto et al. 2008; Mackenzie 2005), A documented trend in certain types of birth defects, most notably cardiac defects and renal agenesis (Edmond and James 1990; Vu 2008; Harris 2007)

Presentation Notes: It has been known for some time that exposure to certain substances in the environment—whether encountered incidentally or ingested deliberately—can have reproduction-related effects. Here are some examples of reproduction-related effects of environmental exposures. Tobacco smoke—Active or passive smoking increases the risk of miscarriage, impairs fertility, and decreases semen quality. It is also causally identified as a risk factor for low birth weight and preterm birth. Alcohol—Heavy drinking during pregnancy is linked to fetal alcohol syndrome as well as other risks to the developing fetus, including mental retardation, behavioral problems, and birth defects. Metals—Exposure to lead and mercury increases the risks of fetal loss, impaired fertility, menstrual irregularities, abnormal sperm, and altered pubertal onset. Toluene—Excessive (incidental or deliberate) inhalation of toluene (a chemical found in paint thinners and other solvents) during pregnancy is linked to fetal solvent syndrome, a condition marked by facial abnormalities, small head size, and low birth weight. DBCP—The pesticide 1,2-dibromo-3-chloropropane (DBCP) has been found to cause low sperm counts and other male reproductive effects.

Presentation Notes: This slide set reviews:, The state of the science on the reproduction-related effects of exposure to certain types of potentially harmful chemicals and heavy metals encountered every day in the environment, The critical windows of susceptibility during which environmental exposures are most likely to have reproduction-related effects, General principles to guide counseling of patients, Sources of further information and resources for clinicians to help counsel patients

Presentation Notes: Some facts about chemical production in the United States:, Tens of thousands of chemicals are in commercial use, and on average, more than 700 new chemicals are introduced into commerce each year. Although these chemicals are an integral component in the production of important goods and services, some may be toxic and may adversely affect human health and/or the environment. It was in this context that Congress passed the Toxic Substances Control Act in 1976. The Act authorized the Environmental Protection Agency (EPA) to obtain information from chemical manufacturers on the risks of chemicals and to control those that the EPA determines will pose an unreasonable risk. EPA does not routinely assess the human health and environmental risks of existing chemicals and faces challenges in obtaining the information necessary to do so. Of the 87,000 chemicals registered for commerce in the United States:, Only about 8,000, or one-tenth, have been tested for potential health effects. Of those that have been tested, effects on reproductive health may not have been assessed. About 3,000 are produced or imported in quantities of more than 1 million pounds annually. About 75,000 are on EPA’s Toxic Substances Control Act (TCSA) Chemical Substances Inventory. (Congress passed the TSCA in 1976 to regulate chemicals used in the United States and to ensure that they do not pose any unreasonable risks to human health or the environment. However, the reproductive and environmental effects of these chemicals are not always tested.)

Presentation Notes: Genes and gene expression, social environments, diet and nutrition, and exposure to environmental toxicants all interact with one another to affect reproductive health and the development of the fetus or child. These factors interact to increase or decrease resilience to environmental exposures.

Presentation Notes: For at least some chemicals, [CLICK], Chemicals may be present in water, air, soil, or manufactured products. [CLICK], Chemicals can enter the body through inhalation, ingestion, or skin contact. This is the point of biologic uptake, or exposure. [CLICK], They then can travel to a target organ, such as the testes or ovaries, where they affect biological processes…, [CLICK], …which leads to a clinical effect.

Presentation Notes: Data from biomonitoring studies provide valuable information about the specific chemical exposures in individuals and populations. Researchers conduct biomonitoring studies to assess human exposure to chemicals by measuring the chemicals themselves or their metabolites in body tissues and fluids. Advances in analytic chemistry enable scientists to accurately measure the presence of certain chemicals in minute quantities of parts per trillion or even lower. Researchers use these techniques to measure the presence of chemicals in human blood, urine, organ tissues, and breast milk. In many cases, the meaning of the presence of certain chemicals in surveyed populations is not yet clear. Biomonitoring is not new; it has been performed to identify lead in drinking water since 1976, and biomonitoring efforts were expanded in the 1990s.

Presentation Notes: Environmental exposures to toxicants can affect people at all life stages, including before birth and during childhood, adolescence, and adulthood. These exposures can have direct effects at all stages of life, not just during pregnancy. Exposures can influence the ability to conceive and can affect fetal and child development. The effects of environmental exposures can emerge when a couple tries to conceive, [CLICK], during pregnancy once conception has occurred, [CLICK], during the development of the embryo and fetus, [CLICK], in the newborn after birth, [CLICK], or later in life—including that baby’s personal health and eventual fertility as an adult, An online tool called “Critical Windows of Development” is available from The Endocrine Disruption Exchange (TEDX). It provides a timeline of human embryonic/fetal development, along with animal research on low-dose exposure to endocrine-disrupting chemicals (EDCs) during development and altered health outcomes. More information about this online tool will be provided at the end of this presentation.

Presentation Notes: Exposure to environmental toxins during certain critical periods of development has been found to be associated with reproduction-related effects in both animals and humans.

Presentation Notes: Environmental toxicants can affect reproduction and development through a number of mechanisms. For example:, [CLICK], Some chemicals are cytotoxic—they kill cells, and if those cells are oocytes or sperm cells, they can cause sterility. [CLICK], Others may interfere with the function of certain types of cells. [CLICK], Another mechanism is through changing the structure of DNA or changing the way in which genes are expressed.

Presentation Notes: Environmental chemicals can cause DNA-related changes in one of two ways:, [CLICK], They can cause structural changes to DNA, such as mutations and breaks. [CLICK], They can modify the way in which genes are expressed, without causing any changes in the DNA sequence.

Presentation Notes: [CLICK], Structural changes to chromosomes alter the structure of DNA. For example, cytotoxins or radiation…, [CLICK], can directly damage the structure of chromosomes. [CLICK], Which, in turn, can lead to mutagenesis (gene mutations) and effects on germ cells. [CLICK], The outcome may be the inability to conceive or, if conception does take place, birth defects in the offspring. [CLICK], In contrast, functional changes to gene expression do not alter the structure of DNA. [CLICK], Chemicals that disrupt endocrine function may change the way in which genes are expressed, without actually altering DNA sequence. [CLICK], This may lead to alterations in hormone function. [CLICK], Which, in turn, can affect the development of puberty.

Presentation Notes: In these examples, the second mechanism—functional change to gene expression—forms the basis of the field of epigenetics. Epigenetics is a relatively new field that studies the effects of heritable changes in gene expression caused by mechanisms other than changes in the underlying DNA sequence. Epigenetic effects are caused not by internal changes in DNA sequence (as is the case with inherited gene mutations), but may be caused by external environmental factors that modify the activation of certain genes. Epigenetic effects can persist throughout the process of cell divisions for the remainder of a cell’s life. The altered genetic expression may pass from one generation to the next and persist for multiple generations. However, there is no change in the underlying DNA sequence of the organism. Instead, nongenetic factors cause changes in how the organism’s genes are expressed.

Presentation Notes: In the 1990s, a number of studies revealed that adverse environmental conditions and/or exposures—such as poor maternal nutrition—during fetal development could lead to an increased risk of coronary heart disease and other chronic conditions during adulthood. These discoveries led to the Barker Hypothesis, also called the developmental origins of disease hypothesis. The hypothesis states that adverse environmental exposures during critical periods of fetal development can lead to metabolic and endocrinologic diseases later in life. This hypothesis is becoming increasingly well established for a number of diseases and conditions.

Presentation Notes: The effects of environmental exposures may not be only immediate effects but may emerge many years later in the offspring of those exposed. Diethylstilbestrol (DES) is an example of how the effects of environmental exposure during pregnancy can show up in offspring many years later. DES was given to some pregnant women for decades in the mistaken belief that it would prevent miscarriage. In actuality, it was later found that the drug increases the chances of miscarriage, as well as other pregnancy complications.

Presentation Notes: In the early 1970s it was discovered that DES also affected the offspring of these women later in life. Since then, research on DES has revealed that the drug has many adverse effects on DES sons and daughters. DES was never banned in the United States, but its use during pregnancy was discontinued in 1971. It continued to be used for other indications until 1997, when its sole remaining manufacturer stopped production.

Presentation Notes: We now know that a number of male and female reproductive organs and functions are harmed when DES is taken during pregnancy. DES daughters and sons are just now reaching the age when cancers of the reproductive organs normally develop. Studies in animals suggest that DES daughters and sons are likely to have increasingly higher rates of these cancers as they age. Animal studies also indicate that maternal DES ingestion during pregnancy can harm the reproductive health of multiple generations. In this slide, the blue text marked by asterisks represents the effects that have been seen in animal studies. Research on DES grandchildren will add to the current body of knowledge.

Presentation Notes: Some recent research on environmental reproductive effects has focused on a group of chemicals known as endocrine-disrupting chemicals, or EDCs. EDCs are chemicals that interfere with hormonal synthesis, metabolism, function, carrier protein levels, and other mechanisms.

Presentation Notes: Polychlorinated biphenyls, commonly called PCBs, are one example of endocrine-disrupting chemicals that have been well studied and are therefore instructive in looking at other EDCs. PCBs were used as coolants and lubricants in electrical equipment before 1977. The main source of exposure to PCBs is food contamination, although levels have been decreasing since their use was banned in 1977.

Presentation Notes: This slide provides examples of potential affects associated with exposure to PCBs.

Presentation Notes: Most toxicological and epidemiological studies of environmental effects on reproductive health have been based on certain assumptions. In many cases, these assumptions may still hold true, but as the science on reproductive toxicants continues to evolve, some of these assumptions are being questioned. Assumption: Safe doses exist below a theoretical threshold. However: For certain toxicants, some studies based on these assumptions have led to high rates of false-negative results, underestimating the effects of very low doses. Assumption: High-dose testing predicts low-dose results. However: For some exposures, contrary to conventional thinking, high-level tests do not always predict low-level impacts. Assumption: The dose-response curve is linear; in other words, the effect of an environmental exposure increases as the dose increases. However: For certain compounds, numerous studies in animals have found significant reproductive effects at low doses—doses to which people are actually exposed in real life. We now understand that genetic expression is vulnerable to environmental causes, and that for many environmental contaminants, low levels of exposure can affect gene expression.

Presentation Notes: Most reproductive environmental health science is based primarily on rigorous animal studies and epidemiological observation. It is not ethically feasible to conduct randomized clinical trials in humans and expose large populations to chemicals that have been shown to produce harmful effects. Studies in animals have found significant reproductive effects at low doses—doses to which people are actually exposed in everyday lives.

Presentation Notes: Supposed “safe” levels of environmental toxicants—when they are determined at all—are often based on limited endpoints as well as political and economic considerations. Epidemiological studies have an inherently limited capacity to identify causal relationships between environmental toxicants and reproduction-related effects, even when those relationships do exist. Environmental effects on reproductive health is a complicated area that is challenged by many contributing factors. Traditional ways of determining “safe” levels are now being challenged, but the relevance of these findings to clinical guidance is not always clear.

Presentation Notes: The Precautionary Principle is an ethical and political principle that can be seen as somewhat akin to the medical principle of “first, do no harm” or the common aphorism, “better safe than sorry.”, With regard to reproductive health and environmental exposures, the Precautionary Principle can be applied to policy-making, to counseling patients, and to personal decision-making.

Presentation Notes: For clinicians, the challenge is to translate population-wide effects into real-life risks for an individual patient. [CLICK], There is a 2%–3% background risk of major birth defects in the population. Environmental exposures may increase the risk above this background, but elimination of exposures will not guarantee a perfect outcome (due to background risk). [CLICK], It is important to remember—and to convey to patients—that elevated risks that are identified in population-wide studies often represent exceedingly small risks to an individual, depending on that person’s vulnerability to the effect.

Presentation Notes: Even a modest increase in risk can translate into a big public health concern if the exposed population is large enough. A large increase in risk will be increasingly important in individuals, even if not very many of them are exposed. If an outcome (e.g. a birth defect) is rare, it will remain rare—and the risk small for individuals—even if the risk doubles or triples. For example, if a chemical increases the risk of a birth defect from 1 in 250,000 to 3 in 250,000, it’s still rare.

Presentation Notes: The next two slides show the effects of a small shift in IQ distribution in a hypothetical population of 260 million. The effect of low lead exposures on IQ is relatively small for the individual with an IQ of around, [CLICK], the average of 100, reducing IQ by only a few points. However, impacts that are marginal for the average individual can have profound effects when applied over large populations. (This is also true for any other cognitive/behavioral function, such as memory or attention.), A slight shift downward shift in IQ will have dramatic effects at the low, [CLICK], and high, [CLICK], ends of the distribution curve—often referred to as the “tails.”, In this graph, the area under the left “tail” of the curve represents the proportion of the population with an IQ of less than 70, the score used to define mental retardation. In a population of 260 million, about 6 million people would fall below this line. The area under the right ”tail” of the curve represents the proportion with an IQ of greater than 130, the score used to define “gifted.”

Presentation Notes: Now see what happens when the average IQ is shifted…, [CLICK], by 5 points, from 100 to 95. [CLICK], Now, 3.2% of the population, or 9.4 million people, have an IQ below 70. [CLICK], This represents a 57% increase in the numbers of individuals defined as mentally retarded. [CLICK], At the same time, the numbers of those considered to be “gifted”—defined as having an IQ of greater than 130—have declined from 6 million to 2.4 million. [CLICK], This represents a 60% decrease in the numbers of individuals defined as gifted. Thus, population-wide shifts in IQ of only a few points can have a dramatic effect on the number of individuals in the low and high ends of the distribution. The impacts on most individuals will go unnoticed. But for people at the low end of the distribution, a small shift can be highly significant. It may, for example, make the difference between independent and institutional living, or employment and unemployment. The impact of a population-wide shift is also significant for society at large. Demands for resources for people with special needs can increase dramatically with small shifts.

Presentation Notes: The question of what to do about environmental exposures is a difficult one for a number of reasons:, Because experiments cannot be carried out in humans for ethical reasons, most of the current scientific knowledge of environmental exposures is based on studies in animals, the results of which cannot always be easily or directly extrapolated to people. That said, there is enough reliable evidence to suggest that some guidance can be offered to patients to avoid or at least limit their exposures where this is practical. Each patient must be considered individually on the basis of his or her particular environmental and personal circumstances and factors. Finally, although some degree of exposure to environmental toxicants is unavoidable, specific changes can and do make a difference.

Presentation Notes: Patient counseling should focus on critical windows of susceptibility for all patients.

Presentation Notes: An environmental history should be incorporated into reproductive health histories of both women and men to determine whether there are potentially harmful exposures and to help guide patients in making decisions. This is especially important at vulnerable stages such as early childhood, puberty, adolescence, preconception planning, and pregnancy.

Presentation Notes: CH2OPS is a helpful memory aid to review the various domains of life in which environmental exposures occur. The CH2OPS domains can be used in the environmental history to ask about a patient’s environmental exposures, as well as to educate and raise awareness about potential harmful exposures. Within each of these domains, clinicians can help guide patients by learning about, and making patients aware of, resources and alternatives in their communities, homes, and personal lives that can help them to minimize their exposure to toxicants. After each of the next several slides, which give examples of where toxicants can be found within each domain, are examples of such resources and alternatives.

Presentation Notes: Sources of exposures to environmental toxicants in the community may exist in urban, suburban, and rural environments. These are some examples of sources of environmental toxicants that may exist in a community’s air, water, and soil.

Presentation Notes: Patients can be counseled to take some practical steps like these to reduce their exposure to environmental toxicants at the community level. There are probably environmental public health groups and resources in your communities that will be able to provide this type of information for your patients.

Presentation Notes: Commonly used chemicals in the home also may be a source of environmental toxicants. Exposure to toxicants may occur through the use of, for example, paints, glues, and solvents; household cleaning products; and automobile care products.

Presentation Notes: Recreational fishing or water sports may increase the risk of exposure to mercury and other contaminants.

Presentation Notes: Some practical things that can be done to reduce or eliminate environmental exposures in the home.

Presentation Notes: Buy organic when possible. If you can’t buy organic, choose the products that have been shown to contain less pesticides.

Presentation Notes: Read labels on cleaning products to be aware of their contents or make your own nontoxic cleaning products with everyday ingredients.

Presentation Notes: The FDA advises children and pregnant women to avoid eating shark, swordfish, king mackerel, and tilefish, which have the highest potential for mercury contamination. Local advisories should be checked for information about the safety of fish caught in local waters.

Presentation Notes: Some practical things can be done to reduce or eliminate environmental exposures when participating in hobbies.

Presentation Notes: Work exposures include exposure to chemicals, radiation, biological agents, pesticides, and other toxicants. Exposure can occur in all types of occupations, including skilled and unskilled labor, office work, and others.

Presentation Notes: Some practical things can be done to reduce or eliminate environmental exposures in the workplace.

Presentation Notes: Some practical things can be done to reduce or eliminate environmental exposures in schools.

Presentation Notes: Personal habits, including diet and consumption of alcohol, tobacco products, and medications; and use of personal care products are other potential sources of exposure.

Presentation Notes: Some practical things can be done to reduce or eliminate environmental exposures in the Personal domain.

Presentation Notes: Low socioeconomic status may increase the risk of exposure to environmental toxicants in communities and neighborhoods.

Presentation Notes: Some practical things can be done to reduce or eliminate environmental exposures in the Socioeconomic domain.

Presentation Notes: When talking to both male and female patients, remember that identifying and reducing exposures to potentially harmful toxicants now increases the likelihood of a successful pregnancy outcome.

Presentation Notes: The ARHP website provides information on environmental and reproductive health, including news articles, continuing education, research, and patient resources.

Presentation Notes: A number of resources for clinicians are available to educate and raise awareness, which will aid in patient counseling. “Critical Windows of Development” is an online tool provided by The Endocrine Disruption Exchange (TEDX). It shows a timeline of human embryonic/fetal development, together with animal research on low-dose EDC exposure and altered health outcomes. ReproTox is an online database for providers and consumers that presents information on more than 5,000 agents and exposures and their reproduction-related effects. TOXNET contains online databases on toxicology, hazardous chemicals, environmental health, and toxic releases.

Presentation Notes: Occupational and environmental health departments in universities are a reliable source of information on environmental health. The American College of Occupational and Environmental Medicine is a membership organization for physicians who specialize in the environmental health and safety of workers, workplaces, and environments. Resources for clinicians are available on its Web site. Hosted by the University of Maryland School of Nursing, EnviRN provides scientific information on environmental health and nursing. Its Databases and Assessment Tools page provides a wealth of information on health effects on humans of environmental exposures, summaries on selected chemicals and sources of potential exposure, Toxicity and Exposure Assessment for Children’s Health (TEACH), access to National Library of Medicine databases, and more.

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