A growing body of scientific evidence suggests that preconception and prenatal exposures can impact fetal development adversely and lead to potential long-lasting health effects. Reproductive health professionals have little training on these exposures and how to counsel patients effectively. We present short summaries of some of the most common environmental exposures and give providers practical tools with which to counsel patients in the clinical setting. These tools may enable practitioners to help prevent harmful environmental exposures and to reduce the risk of future adverse health impacts for the prenatal and preconception patient population.
A large and growing body of scientific literature provides evidence that environmental exposure during the prenatal period can impact fetal development adversely and potentially have long-lasting effects throughout the lifespan. Several well-recognized scientific bodies that include the American Academy of Pediatrics, the Endocrine Society, and the President’s Cancer Panel recognize that some prenatal environmental exposure can be associated with adverse birth outcomes and abnormalities in early childhood development with the potential for long-lasting impacts.
Reproductive health providers have an important role to play in “risk communication” that is associated with environmental health. They can be knowledgeable about these issues and empower their patients to make positive decisions to reduce exposure and to prevent adverse health impacts to both mother and fetus. In an article that described the role of reproductive health providers in the prevention of exposure, Sutton et al summarized the potential environmental threats to the unborn fetus and state that clinicians are in a unique position to provide anticipatory guidance to all patients with information about how to avoid toxic exposures at home, in the community and at work. Although many environmental hazards that can impact the developing fetus are well-recognized in the scientific literature, it is unclear how reproductive health providers can counsel patients effectively regarding these issues. In the current article, we provide practical tools to counsel women regarding some of the most common environmental risks that include lead, mercury, pesticides, and endocrine-disrupting chemicals (EDCs). We have chosen lead, mercury, and pesticides as topics because biomonitoring shows that most of the population is exposed to these chemicals and because published peer-reviewed literature exists to guide screening, counseling, and treatment. We also included EDCs that are emerging contaminants of concern to illustrate how providers can approach guidance in the setting of evolving scientific information. The topics we have chosen are not exhaustive but do represent common exposures in the general population. We present a short summary of background data and discuss approaches to counseling in the prenatal setting. Tables 1-4 contain key points and can be used during the clinical encounter to communicate environmental health-based messaging, exposure-reduction techniques, and references to treatment when applicable and to offer resources for further information. Most women in the prenatal/preconception period experience low-level chronic exposure over time for which providers can counsel about risk and exposure reduction to prevent further disease. Clinicians who are concerned that their patients may be exposed to excessive amounts of environmental or occupational toxicants should call their local poison control center or refer patients to a medical toxicologist. We do not discuss smoking and environmental tobacco-smoke exposure because reproductive health providers already are aware that these exposures lead to adverse health impacts for both the pregnant woman and the developing fetus and because resources to aid in counseling currently exist.
| Messaging | Key points |
|---|---|
| Health-based | Exposure to mercury can come from eating fish, contact with quicksilver, use of skin-lightening creams, or inhalation of mercury vapors at work. |
| Mercury is a potent neurotoxin; exposure during pregnancy can lead to adverse neurodevelopmental outcomes that include lower IQ and poor language and motor development. | |
| Fish is an excellent source of protein and omega-3 fatty acids, which have been shown to improve visual acuity and scores on the Denver Developmental Screen. | |
| Exposure reduction | Pregnant, preconception, and breastfeeding patients should follow US Environmental Protection Agency and state-specific fish consumptions guidelines. |
| To maximize the benefits of fish consumption, eat fish twice per week. | |
| Choose a variety of fish; avoid shark, swordfish, king mackerel, and tile fish. | |
| Eat fish that are lower in mercury. | |
| If you eat recreationally caught fish, access local fish advisories and follow the recommendations for consumption. | |
| Do not use skin-lightening creams or home remedies that might contain mercury. | |
| Resources | Reproductive health providers can access web resources that offer lists of “healthy fish” and species to avoid; patients can use these when grocery shopping or eating out: http://www.doh.wa.gov/ehp/oehas/fish/fishchart.htm and http://www.nrdc.org/health/effects/mercury/guide.asp . |
| Reproductive health providers who suspect mercury toxicity in their patients from very high fish consumption, exposure to metallic mercury, home remedies, or use of skin-lightening creams should contact a toxicologist at their local poison control center ( http://www.aapcc.org/dnn/AAPCC/FindLocalPoisonCenters.aspx ) or an occupational and environmental medicine physician/pediatric environmental health specialist ( www.aoec.org ) for advice on testing and chelation. |
| Messaging | Key points |
|---|---|
| Health-based | Lead is neurotoxic to the developing fetus. |
| Risk factors for lead exposure include recent immigration to the United States, pica practices, occupational exposure, culturally specific practices that include the use of traditional remedies, imported cosmetics, the use of lead-glazed pottery, and renovating or remodeling a home that was built before 1970. | |
| Women at high risk for lead exposure should be screened with a venous blood lead level test. | |
| A maternal blood lead level as low as 10 µg/dL and under is associated with an increased risk of impaired fetal growth and neurodevelopment; higher blood lead level concentrations are associated with birth defects, spontaneous abortion, and gestational hypertension. | |
| A pregnant woman with a blood lead level of ≥5 μg/dL should be counseled to reduce exposure and have follow-up testing | |
| A pregnant woman with a blood lead level of ≥10 μg/dL should be counseled to reduce exposure, to have follow-up testing, and be referred to a local health department for home investigation of lead sources. | |
| Exposure reduction | Never eat or mouth nonfood items (such as clay, soil, pottery, or paint chips) because they may be contaminated with lead. |
| Avoid jobs or hobbies that may involve lead exposure and take precautions to avoid take-home lead dust if a household member works with lead (eg, construction or home renovation/repair in pre-1978 homes and lead battery manufacturing or recycling). | |
| Stay away from repair, repainting, renovation, and remodeling work being done in homes built before 1978 to avoid possible exposure to lead-contaminated dust from old lead-based paint; avoid exposure to deteriorated lead-based paint in older homes; have water tested if you suspect lead contamination from wells or solder in pipes. | |
| Eat a balanced diet with adequate intakes of iron and calcium. | |
| Avoid alternative cosmetics, food additives, and medicines that were imported from overseas. | |
| Shoes should be removed at the door to prevent tracking in lead and other pollutants. | |
| Resources | Reproductive health providers can use the evidence-based guidelines published in 2010 by the Centers for Disease Control and Prevention ( www.cdc.gov/nceh/lead/publications/Leadandpregnancy2010.pdf ) for further information on health impacts of prenatal lead exposure, biomarker measurement, and prevention/management. |
| Reproductive health providers with pregnant patients with blood lead levels of ≥20 μg/dL should contact a toxicologist at their local poison control center ( http://www.aapcc.org/dnn/AAPCC/FindLocalPoisonCenters.aspx ) or an occupational and environmental medicine physician/pediatric environmental health specialist ( www.aoec.org ) for advice on testing and chelation. |
| Message | Key points |
|---|---|
| Health-based | Pesticide exposure can come from eating produce and from using pesticides in your home or on your pets. |
| Exposure to pesticides in pregnancy has been shown to increase the risk of intrauterine growth retardation, congenital anomalies, leukemia, and poor performance on neurodevelopmental testing | |
| Exposure reduction | Avoid the application of pesticides indoors and outdoors, and stay out of areas that have been treated recently. |
| Do not use chemical tick and flea collars or dips. | |
| If you choose to eliminate pests, consider the following options: Use only licensed pesticide applicators. Use baits and traps instead of sprays, dusts, and bombs. | |
| Integrated pest management techniques include the following options: Seal cracks and holes in the outside of the building. Practice good sanitation; remove food, crumbs, and standing water; make sure garbage cans have tight-fitting lids. Hire a company that specializes in integrated pest management. | |
| Consider buying organic produce when possible; focus on the “Dirty Dozen,” which is a list of the 12 most contaminated products that is published by the Environmental Working Group that is available at http://www.ewg.org/foodnews/ . | |
| Wash all fruits and vegetables before eating. | |
| Remove shoes at the door. | |
| Resources | Reproductive health providers who suspect pesticide toxicity in their patients should contact a toxicologist at their local poison control center ( http://www.aapcc.org/dnn/AAPCC/FindLocalPoisonCenters.aspx ) or an occupational and environmental medicine physician/pediatric environmental health specialist ( www.aoec.org ) for advice on testing and treatment. |
| Other useful resources: Safer Pest Control Project that is available at http://www.spcpweb.org/resources/#factsheets . National Pesticide Information Center at http://npic.orst.edu/health/safeuse.html . |
| Message | Key points |
|---|---|
| Health-based | Overall, the health impact of phthalates, bisphenol A, and polybrominated diethyl ethers on the developing fetus are not well understood; current research studies will continue to elucidate potential health impacts. |
| Animal studies suggest that prenatal exposure to bisphenol A are associated with obesity, reproductive abnormalities, and neurodevelopmental abnormalities in offspring. | |
| Human prenatal phthalate exposure is associated with changes in male reproductive anatomy and behavioral changes primarily in young girls. | |
| Human prenatal polybrominated diethyl ethers exposure is associated with changes in prenatal thyroid hormone concentrations, neurodevelopmental abnormalities, and male reproductive tract abnormalities in infancy. | |
| Exposure reduction | We encourage providers to counsel families to prevent endocrine-disrupting chemicals exposure to reduce the potential risk of harm. |
| Overall, women can reduce exposure to phthalates and bisphenol A by (1) reducing the consumption of processed foods, (2) increasing fresh and/or frozen foods, and (3) reducing consumption of canned foods. | |
| Avoid the use of plastics with the recycling codes (often found on the outside bottom of containers) #3 and #7 because they can contain phthalates and/or bisphenol A. | |
| For polybrominated diethyl ethers, foam items that were bought before 2005 should be inspected; anything that is ripped or breaking down should be replaced. | |
| Be careful when removing old carpet because the padding may contain polybrominated diethyl ethers. | |
| Use a vacuum machine that is fitted with a HEPA filter to get rid of dust that may contain endocrine-disrupting chemicals. | |
| When purchasing new products, ask the manufacturers what type of fire retardants were used. | |
| Resources | The National Institutes of Environmental Health Sciences information on bisphenol A for providers and parents: http://www.niehs.nih.gov/news/sya/sya-bpa/ . |
| The Centers for Disease Control and Prevention Public Health statement on the phthalate di(2-ethylhexyl)phthalate: http://www.atsdr.cdc.gov/toxprofiles/tp9-c1-b.pdf . | |
| US Environmental Protection Agency’s website on polybrominated diethyl ethers: http://www.epa.gov/oppt/pbde/ . |
Mercury
Mercury is released into the atmosphere by coal-fired power plants, waste incineration, and other industrial processes and enters waterways by run-off or settling of air-born particulate matter. It is metabolized by microorganisms into methylmercury that then accumulates in fish, concentrating in the tissue. Because large fish eat smaller fish, mercury biomagnifies up the food chain. In the United States, mercury has contaminated 43% of US lakes and wetlands; all 50 states have fish advisories that recommend limits on the ingestion of locally caught fish by pregnant and nursing women and children.
Other forms of mercury such as metallic mercury (“quicksilver”) from broken thermometers and sphygmomanometers and mercuric salts that are found in ethnic home remedies and skin-lightening creams that are sold outside of the United States may also be a source of exposure. Mercury is used in occupational settings, and workers may be exposed by inhalation or dermal contact in the handling of dental amalgams, in glass calibration, in the manufacture of fluorescent lamps in the paper pulp industry, and in chloralkali plants.
Mercury is a potent neurotoxin. The tragedy of Minamata Bay, Japan, in the 1950s (in which villagers who subsisted on fish from the contaminated bay had children who experienced an increase of cerebral palsy, mental retardation, blindness, and other neurologic conditions and congenital anomalies) helped to illuminate the toxicity of methylmercury. More recently, several landmark studies that have examined lower dose exposure that were conducted among pregnant women from high fish consumption populations have shown evidence of poorer neurologic development that is associated with higher levels of mercury exposure during pregnancy. Lower scores on the Denver Developmental test, the Bayley Psychomotor Development index, and the Neonatal Assessment Behavioral Scale were all associated with higher cord blood mercury, higher maternal hair mercury concentrations, and the consumption of fish at least 3 times per week during pregnancy. Mercury exposure has also been associated with shorter duration of pregnancy. In the past decade, several studies that combined data on fish consumption frequency questionnaires and mercury levels in hair, blood, and cord blood have estimated that 5-8% of pregnant women may have mercury levels above the recommended limits.
Increasing awareness of the potential adverse effects of methylmercury to the developing fetus has caused many pregnant women to decrease their consumption of fish or eliminate it entirely from their diets. It should be recognized that fish is an excellent low-fat source of protein and omega-3 fatty acids. There is some evidence to show that fish consumption or omega-3 supplementation during pregnancy may increase the duration of gestation and birthweight in some populations. Improved visual acuity, performance on developmental testing, and higher IQ scores have all been associated with the consumption of omega 3s and fish in pregnancy.
The fish consumption message is complex, but important, because women should be encouraged to eat fish to gain the benefits of the omega-3s, yet they need to “choose wisely” to avoid the potential risk of adverse pregnancy effects. The US Environmental Protection Agency provides fish consumption guidelines for pregnant and nursing women, women of child-bearing age, and young children that include recommendations to eat fish twice per week (total of 12 oz), avoid fish that are highest in mercury (which includes king mackerel, shark, swordfish, and tile fish) and to follow local fish advisories for recreationally caught fish ( Table 1 ).
Reproductive health providers should screen their patients who are pregnant or nursing or who are in the preconception phase with questions such as, “How often do you eat fish?”, “What types of fish do you eat?”, and “Do you eat recreationally caught fish?” Regarding other sources of exposure to mercury, providers should ask, “Do you use skin-lightening creams or other personal care products that contain mercury? Do you have a mercury thermometer at home? Do you work with mercury?”
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
