Describe the attitudes, beliefs, and practices of U.S. obstetricians on the topic of prenatal environmental exposures.
A national online survey of American Congress of Obstetricians and Gynecologists (ACOG) fellows and 3 focus groups of obstetricians.
We received 2,514 eligible survey responses, for a response rate of 14%. The majority (78%) of obstetricians agreed that they can reduce patient exposures to environmental health hazards by counseling patients; but 50% reported that they rarely take an environmental health history; less than 20% reported routinely asking about environmental exposures commonly found in pregnant women in the U.S.; and only 1 in 15 reported any training on the topic. Barriers to counseling included: a lack of knowledge of and uncertainty about the evidence; concerns that patients lack the capacity to reduce harmful exposures; and fear of causing anxiety among patients.
U.S. obstetricians in our study recognized the potential impact of the environment on reproductive health, and the role that physicians could play in prevention, but reported numerous barriers to counseling patients. Medical education and training, evidence-based guidelines, and tools for communicating risks to patients are needed to support the clinical role in preventing environmental exposures that threaten patient health.
Citation: Stotland NE, Sutton P, Trowbridge J, Atchley DS, Conry J, Trasande L, et al. (2014) Counseling Patients on Preventing Prenatal Environmental Exposures - A Mixed-Methods Study of Obstetricians. PLoS ONE9(6): e98771. https://doi.org/10.1371/journal.pone.0098771
Editor: Aimin Chen, University of Cincinnati, United States of America
Received: January 13, 2014; Accepted: May 7, 2014; Published: June 25, 2014
Copyright: © 2014 Stotland et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: Financial support for this survey was provided to UCSF Program on Reproductive Health and the Environment by: New York Community Trust, Passport Foundation, Johnson Family Foundation, the National Institute for Environmental Health Sciences (ES018135) and United States Environmental Protection Agency STAR (RD83467801). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Exposure to hazardous environmental chemicals, i.e., manufactured chemicals and metals, is linked to adverse health outcomes across all stages of the human life cycle including fertility, conception, pregnancy, child and adolescent development, and adult health –. Human exposure to environmental chemicals is ubiquitous. A population-based study found that virtually all pregnant women in the U.S. had measureable levels of at least 43 different environmental chemicals in their bodies, including chemicals that were measured at levels similar to those associated with adverse developmental and reproductive health outcomes in epidemiologic studies . There are currently over 80,000 chemicals in commerce , , and exposure occurs through air, water, food and consumer products in the home and workplace. The majority of industrial chemicals have not been tested for potential reproductive/developmental harm .
Obstetricians are uniquely positioned to help prevent exposures to environmental chemicals with adverse developmental and reproductive health effects . Pregnancy is a time when exposure to environmental contaminants can disrupt or interfere with the physiology of a cell, tissue, or organ , leading to permanent and lifelong adverse health outcomes that may be passed down to future generations . Pregnancy is also an opportune time to prevent harmful exposures as it is a period when patient interest about health can be extremely high.
While obstetricians might play a role in preventing exposure to toxic chemicals among pregnant women, empirical evidence of whether or how obstetricians in the US are addressing the evidence that links environmental exposures to adverse reproductive health outcomes is lacking. Accordingly, we undertook the first study to examine attitudes, beliefs and practices among U.S. obstetricians about environmental exposures and their prenatal patients' health.
Materials and Methods
The objective of this study was to assess the attitudes, beliefs and practices of obstetricians regarding prenatal environmental exposures through a mixed methods study including a national, quantitative survey of American Congress of Obstetricians and Gynecologists (ACOG) fellows and a qualitative focus group study of San Francisco Bay Area obstetricians. The protocol for this mixed methods study was approved by the University of California, San Francisco's Committee on Human Research.
We developed a 64-question survey to evaluate obstetricians' attitudes, beliefs, and practices related to environmental health which built upon on the survey of pediatricians developed and utilized by Trasande et al (2006) . The adapted survey was pilot-tested and approved for use by ACOG.
ACOG is the largest U.S. organization of obstetricians with a membership exceeding 52,000, including over 28,000 “fellows.” ACOG fellows are physicians who are board certified in obstetrics and gynecology and are dues-paying members of the organization. All fellows were emailed the survey by ACOG in three “blasts” between September and November, 2011. The email message contained an invitation to participate in the study, a link to the online survey and an offer to enter into a raffle for an iPad as incentive for survey completion. Fellows were eligible to complete the survey if they were currently providing prenatal care.
Part 1 of the survey collected data on obstetricians' demographics and the characteristics of their patient populations. In part two of the survey, obstetricians rated statements about their attitudes, beliefs and practices around reproductive environmental health. We asked about the importance and impact of prenatal environmental exposures; the frequency with which they talked with their patients about environmental exposures; whether or not they counseled patients about 19 specific environmental exposures, their training in environmental health; and what sources of information they trusted about prenatal environmental exposures. We also asked about the choices they make in their own households regarding environmental exposures.
Statistics were calculated using STATA 12 (StataCorp. 2011. Stata Statistical Software: Release 12. College Station, TX: StataCorp LP). The survey was conducted electronically, and data were directly imported and cleaned in STATA. In addition to descriptive statistics, we developed 3 scores—on the obstetricians' clinical practice, their beliefs, and their personal household practices—by averaging the results of the questions pertaining to each of the 3 categories. We compared scores among men and women and among age groups. We used a Wilcoxon rank-sum test to compare the obstetricians' confidence in taking a history on and discussing the impact of cigarette smoking with their patients compared to their confidence in discussing lead, pesticides, mercury and Bisphenol-A (BPA) exposures with their patients.
Qualitative Focus Group Study
A convenience sample of obstetricians was drawn from a variety of settings in the San Francisco Bay Area, including private practice, academic health centers, county hospitals, and a large Health Maintenance Organization (HMO). We used publicly-available lists of local obstetricians as well as personal contacts, asking recipients to forward the message to colleagues. In collaboration with ACOG, we emailed invitations to all ACOG District IX (California) fellows.
Potential participants were screened for eligibility by telephone or email. Obstetricians were eligible if they currently saw pregnant patients in their practice, were ≥3 years post-residency training, and were either generalists or maternal-fetal-medicine specialists. Recruitment ceased when we signed up enough obstetricians for three focus groups with 6–10 participants per group.
The same person moderated every focus group. Sessions lasted approximately 90 minutes. Four investigators observed the focus groups and took field notes. Sessions were audiotaped and transcribed by a professional transcription service (PSF Transcription, San Francisco, CA). Transcripts were reviewed for accuracy by the same 4 investigators that observed the groups. Each participating obstetrician provided written informed consent and completed a written survey to collect demographic and medical practice information. Obstetricians were reimbursed $200 for participation in the focus group.
Using principles of thematic analysis  and a subjective, interpretive “editing style” , we explored obstetricians' attitudes, beliefs, and practices regarding environmental exposures during pregnancy. Four investigators independently read transcripts, identifying prominent ideas and drafting preliminary coding categories. We then engaged in an inductive process of reading and manually coding transcripts, re-organizing coded data into themes. We reviewed results using memos to identify emerging themes and describe relationships among coding categories, as described in Miller and Crabtree (1999) . The final coding scheme and analysis of the findings were reviewed and discussed until consensus was reached.
Of the 24,204 fellows that were on ACOG's email list and sent the email blasts, 2,624 responded and 110 were excluded because they were not currently seeing patients (n = 87) or they did not answer eligibility questions (n = 23). Table 1 presents demographic data on the 2,514 remaining obstetricians included in the analysis.
Based on 2008 data from ACOG, approximately 75% of its fellows were practicing general obstetrician-gynecologists, obstetricians only, or maternal-fetal medicine specialists . Therefore, we calculated that 18,153 ACOG fellows were eligible for the survey, giving us a response rate of 14%. Our findings represented practicing obstetricians from all 50 states and districts from across the country and the age and sex of our respondents corresponded with the statistics reported for ACOG at large in 2011 .
Comparing the difference of scores for clinical practice, beliefs, and personal practices among men and women we found that women had slightly higher scores than men (clinical practice p-value <0.0000; belief p-value = 0.001; personal practice p-value <0.0000); that is women tended to agree more with statements about environmental health and reported doing more to prevent exposures with their families. However we found no association with age and clinical practice, beliefs and personal practices.
Table 2 presents the survey results of obstetricians' self-reported attitudes, beliefs and confidence around environmental health. The majority agreed or strongly agreed that that conducting an environmental health history would help identify patient exposures (86%) and would help women prevent harmful exposures (80%). The majority (77%) of respondents also “strongly disagreed” or “disagreed” with statement that taking an environmental health history “would not be necessary”. Approximately half of the respondents “strongly disagreed” or “disagreed” that taking an environmental health history “would take too much time” (46%) and “would cause needless anxiety for patients” (45%).
Seventy-eight percent of respondents reported they “strongly agreed” or “agreed” that they can reduce patient exposures to environmental health hazards by counseling patients and giving recommendations (mean ± SD = 2.1±0.9; 1 strongly agree – → 5 strongly disagree); yet half of the obstetricians surveyed (50%) reported they rarely (0–20% of the time) take an environmental health history (61% reported taking an environmental health history less than 40% of the time). Additionally, only 1 in 15 received training specific to taking an environmental health history.
Virtually all respondents (99%) reported counseling prenatal patients about cigarette smoking, alcohol, weight gain, and diet/nutrition routinely; in contrast, less than 20% reported routinely counseling about environmental exposures commonly found in pregnant women in the U.S. such as phthalates, BPA, pesticides and PCBs (See Figure 1).
Environmental exposures routinely discussed by less than 50% of survey respondents are shaded light grey. VOCs = volatile organic compounds; PCBs = polychlorinated biphenyls; BPA = bisphenol-A.
When asked to select resources they used for information concerning environmental exposures, 75% of obstetricians surveyed selected ACOG as a primary source of information and guidance, followed by government websites (58%) and the professional literature (57%). Likewise, 89% chose ACOG as the most helpful source for learning new information regarding prenatal health issues.
We conducted three focus groups totaling 22 obstetricians between October of 2011 and January 2012. There were 20 female and 2 male obstetricians, and the mean age of participants for all three groups was 43 (range 32 to 63). Eight of the providers practiced in a public or community clinic, hospital or health center; four were private practice exclusively; six were private practice, but not exclusively HMO; one practiced in a teaching setting; and one practiced in a research setting. All participants were generalist OB/GYNs. The following key themes emerged in data analysis, and example quotes from the focus group transcripts are shown in Table 3.
Obstetricians feared broaching the topic of environmental health with patients, especially regarding chemicals other than lead and mercury. They felt they did not have adequate knowledge and understanding to answer patients' questions about exposures, and that this conversation would take time away from easier topics to address, like nutrition. The sheer number of chemicals in the environment was felt to be a barrier to addressing harmful exposures. Obstetricians were also concerned about harming patients by causing anxiety about exposures they could neither control nor understand; or making patients feel guilty if an adverse clinical outcome occurred.
Participants expressed uncertainty regarding the degree of harm from environmental exposures because they do not feel confident in environmental health data in general, and/or because they believe that the evidence is inconclusive for particular exposures, and therefore not strong enough to merit action. With limited time for visits, participants prioritized obesity and diet counseling, which were felt to be more definitively linked to adverse health outcomes compared to environmental exposures.
This theme addressed “agency” i.e., the ability of patients to take action to reduce risk. This included concerns that patients, because of poverty, low literacy, and cultural factors, would be unable to take action to reduce harmful exposures. Participants struggled to help patients balance concerns about occupational risk with concerns about job loss and economic hardship. In contrast, providers with patients of higher socioeconomic status asked patients to do their own research and take ownership of their own choices.
Resources and Strategies.
This theme considered the resources and strategies obstetricians used when counseling about prenatal environmental exposures. Participants preferred to refer to specialists including geneticists, or to an educational session in a class or group setting, rather than to counsel patients themselves. In each focus group, online resources were chosen as the most useful, but only if generated by a reliable authority such as ACOG or the Environmental Protection Agency (EPA). Concise printed materials with straightforward recommendations were also mentioned as a needed resource.
This is the first study to examine attitudes, beliefs and practices among U.S. obstetricians about prenatal environmental exposures. We found that obstetricians recognized the impact of the environment on reproductive health, but lacked training, time, and tools to take action to prevent harmful exposures. Survey participants believed that environmental exposures were important and that reproductive health professionals had a role in prevention. However, this concern did not translate into clinical practice. Few respondents reported routine counseling about exposure to environmental chemicals known to be harmful to reproductive health, and most felt ill-prepared to deal routinely with the issue.
Lack of certainty about the absolute and relative risk to patients from environmental exposures was a major factor in limiting obstetricians' ability to effectively counsel patients. Good clinical practice demands a level of scientific certainty and considers risks and benefits when advising patients about medical interventions. However, these hallmarks of clinical decision-making do not apply seamlessly to patients' environmental exposures. This is because, in contrast to pharmaceuticals, patient exposure to environmental chemicals generally occurs in the absence of evidence of safety and risk/benefit analyses , , . Patient counseling for environmental exposures is comparable to a decision-logic for advising patients about taking a drug prior to its proven safety, where, in the absence of a compelling benefit, one would likely take a precautionary approach and recommend avoiding exposure.
In addition, there are inherent uncertainties in the evidence generated in environmental health science, which relies on toxicological non-human data and human observational studies. This type of scientific evidence is unfamiliar to, and/or perceived to be, “low quality” by physicians who consider randomized controlled trials (RCTs) as the “gold standard” evidence. However, ethics virtually precludes the use of RCTs in environmental health, and in vitro animal studies of reproductive and developmental toxicity serve as reliable predictors of human health effects –, with studies showing that humans are at least as sensitive as the most sensitive animal species , .
Consistent with a “precautionary” approach to reducing risk in the absence of causal evidence, the Royal College of Obstetricians and Gynaecologists recently concluded: “Despite uncertainty surrounding the effects of common environmental chemicals, mothers should be made aware of the sources and routes of exposure, the potential risks to the fetus/baby and the important role that the mother can play in minimizing her baby's chemical exposure” . They state that such information should be provided at obstetrical visits. Efforts are underway to create evidence-based guidelines by adopting the systematic and transparent methods empirically demonstrated as superior in the clinical sciences to the evidence that informs environmental health .
Another key finding is that over ½ of providers were concerned that raising the topic of environmental exposures to their pregnant patients would cause excessive anxiety and stress. This fear may be unwarranted, as biomonitoring studies have shown that women want to know and can react in a productive way to information about potentially harmful exposures –. However, these same studies also report that some women experience distress from the uncertainty of 1) the degree of harm caused by exposures and 2) a lack of information about how to reduce exposures. It thus seems logical that the focus in clinical counseling should be on the chemicals or substances that are most likely to cause harm and have practical strategies for reducing exposures on the individual level. More research studying pregnant women's responses to messages about environmental health would be helpful in designing counseling tools and interventions.
Our survey findings were limited by a low (14%) response rate and are not representative of all practicing U.S. obstetricians. Strengths of our survey findings include the fact that fellows from all U.S. states were represented in the sample, and our large sample size of over 2,000 respondents. Selection bias may have influenced the results if obstetricians interested in environmental health were more likely to participate. If so, our results would likely overestimate both the importance obstetricians place on environmental health and how often they counsel their patients about the topic.
The qualitative portion of our study was limited by small sample size and a single geographic region that may be more interested in environmental health than other locales. Accordingly, these findings are also not generalizable to all obstetricians across the U.S. However, the consistency between the responses of our Bay Area focus group participants and those of our national ACOG survey provided some validation of our qualitative results. Consistent with the goal of the survey, our findings do provide important insights into the attitudes, beliefs, and practices of U.S. obstetricians on the topic of prenatal environmental exposures that can be tested with more precision for training, regional, practice and other potential variation in future studies.
Our results were consistent with the fact that medical school and residency curricula do not typically include reproductive environmental health , . Current efforts to include how environmental exposures impact patient health in curricula should be expanded, and CME should be provided to inform practicing obstetricians. Obstetricians in our study reported they needed evidence-based information to counsel patients, and that information vetted and supported by ACOG would be the most trusted. After our data were collected, ACOG released a Committee Opinion on “Exposure to Toxic Environmental Agents” that will be useful in guiding both policy and practice among obstetricians and other clinicians . Many other professional societies and clinical organizations have recognized the impact that the environment can have on reproduction . Our results underscore the role that health professional societies can play in operationalizing these statements, by providing trusted science-based guidelines for physicians and other reproductive health professionals.
Our focus group participants believed that their most vulnerable patients are less able to prevent exposures due to poverty, low literacy, and cultural factors. Women of lower socioeconomic status and women of color carry greater risk for environmental exposures –, so it is concerning that the obstetricians in our study reported barriers to counseling those who are most vulnerable. Culturally and linguistically appropriate educational materials are needed to increase patient and community knowledge and awareness of the issue. Patient-centered brochures in English and Spanish that may help clinicians provide this important information to their patients can be downloaded at: http://prhe.ucsf.edu/prhe/toxicmatters.html.
Actions patients can take to reduce body burdens of some harmful substances include switching to organic food , , eating low-fat or non-fat dairy products and meat sparingly, avoiding fish high in mercury, and avoiding fast food and processed foods whenever possible , , Informed patients can also choose cheap, effective and less toxic alternatives for pest control and household cleansers. However, for certain routes of exposure, such as air and water pollution, individual action alone may be ineffective in preventing harmful exposures –. Additionally, women with occupational exposures have limited legal protections as regulations do not always reflect well-documented chronic health impacts. A 2007 study by the California Environmental Protection Agency found that 5 of 19 workplace chemicals known to cause reproductive or developmental harm lack a permissible exposure limit and 14 are not regulated as reproductive hazards . Thus, physician and health professional societies can help reduce harmful exposures for pregnant women by lending their support for policy change.
In conclusion, U.S. obstetricians surveyed recognized some impact of environmental exposures on reproductive health, but lacked training, time, and tools to counsel patients. Incorporating ongoing scientific discovery into medical education and training, developing evidence-based recommendations for prevention, crafting effective and efficient tools for communicating uncertainty and risk to patients, and leveraging the voice of health professionals in policy arenas, are all essential strategies for reducing harmful environmental exposures and improving health outcomes.
Conceived and designed the experiments: BG NES TJW JC. Performed the experiments: DSA PS AC. Analyzed the data: NES JT DSA BG PS AC. Wrote the paper: NES DSA PS JT TJW. Coordination with ACOG for survey distribution: JC. Developed survey that was model for the survey in this paper: LT.
- 1. Woodruff TJ, Carlson A, Schwartz JM, Giudice LC (2008) Proceedings of the summit on environmental challenges to reproductive health and fertility: executive summary. Fertil Steril 89: e1–e20.
- 2. Sutton P, Woodruff TJ, Perron J, Stotland N, Conry JA, et al. (2012) Toxic environmental chemicals: the role of reproductive health professionals in preventing harmful exposures. Am J Obstet Gynecol 207: 164–173.
- 3. Diamanti-Kandarakis E, Bourguignon JP, Giudice LC, Hauser R, Prins GS, et al. (2009) Endocrine-disrupting chemicals: an Endocrine Society scientific statement. Endocr Rev 30: 293–342.
- 4. Grandjean P, Bellinger D, Bergman A, Cordier S, Davey-Smith G, et al. (2008) The faroes statement: human health effects of developmental exposure to chemicals in our environment. Basic & clinical pharmacology & toxicology 102: 73–75.
- 5. Reuben SH, President's Cancer Panel (2010) Reducing Environmental Cancer Risk: What We Can Do Now. Bethesda: National Cancer Institute.
- 6. Woodruff TJ, Zota AR, Schwartz JM (2011) Environmental chemicals in pregnant women in the US: NHANES 2003–2004. Environ Health Perspect 119: 878–85.
- 7. U.S. Environmental Protection Agency (2011) TSCA chemical substance inventory: basic information. Washington, D.C.
- 8. U.S. Environmental Protection Agency (2007) Office of Pollution Prevention and Toxics Programs. Washington, D.C.
- 9. Vogel SA, Roberts JA (2011) Why The Toxic Substances Control Act Needs An Overhaul, And How To Strengthen Oversight Of Chemicals In The Interim. Health Aff (Millwood) 30: 898–905.
- 10. Newbold R, Heindel J (2010) Developmental Exposures and Implications for Early and Latent Disease. In: Woodruff TJ, Janssen SJ, Guillette LJ, Jr, Giudice LC, eds. Environmental impacts on reproductive health and fertility. New York, NY: Cambridge University Press.
- 11. Trasande L, Boscarino J, Graber N, Falk R, Schechter C, et al. (2006) The environment in pediatric practice: a study of New York pediatricians' attitudes, beliefs, and practices towards children's environmental health. Journal of urban health: bulletin of the New York Academy of Medicine 83: 760–772.
- 12. Rice PL, Ezzy D (1999) Qualitative research methods: A health focus. Oxford: Oxford University Press Melbourne.
- 13. Strauss A, Corbin J (2007) Basics of qualitative research: Techniques and procedures for developing grounded theory. Los Angeles: Sage Publications, Incorporated.
- 14. Miller WL, Crabtree BF (1999) Doing qualitative research. Los Angeles: Sage Publications, Inc.
- 15. American Congress of Gynecologists and Gynecologists (2008) 2008 Socioeconomic Survey of ACOG Fellows. Available: http://www.acog.org/About_ACOG/ACOG_Departments/Practice_Management_and_Managed_Care/2008_Socioeconomic_Survey_of_ACOG_Fellows. Accessed 2014 May 12.
- 16. Rayburn WF (2011) The Obstetrician/gynecologist Workforce in the United States: Facts, Figures, and Implications. Washington, D.C.: American Congress of Obstetricians and Gynecologists. Available to ACOG members: http://www.acog.org/Resources%20And%20Publications/The%20Ob-Gyn%20Workforce/The%20Obstetrician-Gynecologist%20Workforce%20in%20the%20United%20States.aspx. Accessed 2014 May 12.
- 17. Wilson MP, Schwarzman MR (2009) Toward a new US chemicals policy: Rebuilding the foundation to advance new science, green chemistry, and environmental health. Environ Health Perspect 117: 1202.
- 18. Raffensperger C, Tickner J (1999) Protecting Public Health and the Environment: Implementing the Precautionary Principle. Washington, DC: Island Press.
- 19. Nisbet ICT, Karch NJ (1983) Chemical Hazards to Human Reproduction. Park Ridge, NJ: Noyes Data Corp.
- 20. Nemec MD, Kaufman LE, Stump DG, Lindstrom P, Varsho BJ, et al. (2006) Significance, Reliability, and Interpretation of Developmental and Reproductive Toxicity Study Findings. Developmental Reproductive Toxicology: A Practical Approach: Informa Healthcare.
- 21. Kimmel CA, Holson JF, Hogue CJ, Carlo G (1984) Reliability of Experimental Studies for Predicting Hazards to Human Development NCTR Technical Report for Experiment No 6015. Jefferson, AR.
- 22. Hemminki K, Vineis P (1985) Extrapolation of the evidence on teratogenicity of chemicals between humans and experimental animals: chemicals other than drugs. Teratog Carcinog Mutagen 5: 251–318.
- 23. National Research Council (U.S.) Committee on Developmental Toxicology, National Research Council (U.S.) Commission on Life Sciences (2000) Scientific frontiers in developmental toxicology and risk assessment. Washington, DC: National Academy Press.
- 24. Bellingham M, Sharpe RM, Royal College of Obstetricians and Gynaecologists (2013) Chemical Exposures During Pregnancy: Dealing with Potential, but Unproven, Risks to Child Health. In: Scientific Advisory Committee, ed. Scientific Impact Paper No 37. London: Royal College of Obstetricians and Gynaecologists.
- 25. Woodruff TJ, Sutton P (2011) The Navigation Guide Work Group (2011) An Evidence-Based Medicine Methodology To Bridge The Gap Between Clinical And Environmental Health Sciences. Health Aff (Millwood) 30: 931–37.
- 26. Wu N, McClean MD, Brown P, Aschengrau A, Webster TF (2009) Participant experiences in a breastmilk biomonitoring study: a qualitative assessment. Environmental Health 8: 4.
- 27. Adams C, Brown P, Morello-Frosch R, Brody JG, Rudel R, et al. (2011) Disentangling the exposure experience: the roles of community context and report-back of environmental exposure data. J Health Soc Behav 52: 180–196.
- 28. Altman RG, Morello-Frosch R, Brody JG, Rudel R, Brown P, et al. (2008) Pollution comes home and gets personal: women's experience of household chemical exposure. J Health Soc Behav 49: 417–435.
- 29. Morello-Frosch R, Brody J, Brown P, Altman R, Rudel R, et al. (2009) Toxic ignorance and right-to-know in biomonitoring results communication: a survey of scientists and study participants. Environmental Health 8: 6.
- 30. Sathyanarayana S, Focareta J, Dailey T, Buchanan S (2012) Environmental exposures: how to counsel preconception and prenatal patients in the clinical setting. Am J Obstet Gynecol 207: 463–70.
- 31. The American College of Obstetricians and Gynecologists Committee on Health Care for Underserved Women, American Society for Reproductive Medicine Practice Committee, The University of California San Francisco Program on Reproductive Health and the Environment (2013) Exposure to toxic environmental agents. Committee Opinion No. 575. Obstet Gynecol 122: 931–935.
- 32. U.C.S.F. Program on Reproductive Health and the Environment (2012) Professional Statements Database. San Francisco, CA. Available: http://prhe.ucsf.edu/prhe/professionalstatements.html.Accessed 2014 May 12.
- 33. Adamkiewicz G, Zota AR, Fabian MP, Chahine T, Julien R, et al. (2011) Moving Environmental Justice Indoors: Understanding Structural Influences on Residential Exposure Patterns in Low-Income Communities. Am J Public Health 101: S238–245.
- 34. Gee GC, Payne-Sturges DC (2004) Environmental health disparities: a framework integrating psychosocial and environmental concepts. Environ Health Perspect 112: 1645–53.
- 35. Morello-Frosch R, Zuk M, Jerrett M, Shamasunder B, Kyle AD (2011) Understanding the cumulative impacts of inequalities in environmental health: implications for policy. Health Aff (Millwood) 30: 879–87.
- 36. Woodruff TJ, Parker JD, Kyle AD, Schoendorf KC (2003) Disparities in exposure to air pollution during pregnancy. Environ Health Perspect 111: 942–6.
- 37. Lu C, Toepel K, Irish R, Fenske RA, Barr DB, et al. (2006) Organic diets significantly lower children's dietary exposure to organophosphorus pesticides. Environ Health Perspect 114: 260.
- 38. Smith-Spangler C, Brandeau ML, Hunter GE, Bavinger JC, Pearson M, et al. (2012) Are organic foods safer or healthier than conventional alternatives?: a systematic review. Ann Intern Med 157: 348–366.
- 39. Rudel RA, Gray JM, Engel CL, Rawsthorne TW, Dodson RE, et al. (2011) Food packaging and bisphenol A and bis (2-ethyhexyl) phthalate exposure: findings from a dietary intervention. Environ Health Perspect 119: 914–920.
- 40. Ji K, Lim Kho Y, Park Y, Choi K (2010) Influence of a five-day vegetarian diet on urinary levels of antibiotics and phthalate metabolites: A pilot study with "Temple Stay" participants. Environ Res 110: 375–82.
- 41. Sathyanarayana S, Alcedo G, Saelens BE, Zhou C, Dills RL, et al. (2013) Unexpected results in a randomized dietary trial to reduce phthalate and bisphenol A exposures. Journal of exposure science & environmental epidemiology 23: 378–384.
- 42. Lubick N (2011) Advising Parents in the Face of Scientific Uncertainty: An Environmental Health Dilemma. Environ Health Perspect 119: a436–a41.
- 43. Adler NE, Stewart J (2009) Reducing obesity: motivating action while not blaming the victim. Milbank Q 87: 49–70.
- 44. California Environmental Protection Agency Office of Environmental Health Hazard Assessment Reproductive and Cancer Hazard Branch (2007) Occupational Health Hazard Risk Assessment Project for California: Identification of Chemicals of Concern, Possible Risk Assessment Methods, and Examples of Health Protective Occupational Air Concentrations. Sacramento: California Environmental Protection Agency.