Preconception Matters, Too: EDC Impacts on Reproductive Health and Development

January 28, 2021
1:00 pm US Eastern Time

Slides & Resources


Kim Harley: Association of phthalates, parabens and phenols in personal care products with pubertal timing in girls and boys.

Carmen Messerlian and Yu Zhang: Maternal and Paternal Preconception, Endocrine Disrupting Chemicals, Exposure and Birth Outcomes.


Kim G HarleyKimberly P BergerKatherine KogutKimberly ParraRobert H LustigLouise C GreenspanAntonia M CalafatXiaoyun YeBrenda Eskenazi. (2019). Association of phthalates, paragons and phenols found in personal care products with pubertal timing in girls and boys. Human Reprod. 34(1):109-117. https://doi.org/10.1093/humrep/dey337.

Berkeley, CERCH. CHAMACOS Study.

Mustieles, V., Zhang, Y., Yland, J., Braun, J. M., Williams, P. L., Wylie, B. J., Attaman, J. A., Ford, J. B., Azevedo, A., Calafat, A. M., Hauser, R., & Messerlian, C. (2020). Maternal and paternal preconception exposure to phenols and preterm birth. Environment international137, 105523. https://doi.org/10.1016/j.envint.2020.105523

Zhang, Y., Mustieles, V., Yland, J., Braun, J. M., Williams, P. L., Attaman, J. A., Ford, J. B., Calafat, A. M., Hauser, R., & Messerlian, C. (2020). Association of Parental Preconception Exposure to Phthalates and Phthalate Substitutes with Preterm Birth. JAMA network open3(4), e202159. https://doi.org/10.1001/jamanetworkopen.2020.2159

Messerlian, C., Braun, J. M., Mínguez-Alarcón, L., Williams, P. L., Ford, J. B., Mustieles, V., Calafat, A. M., Souter, I., Toth, T., Hauser, R., & Environment and Reproductive Health (EARTH) Study Team (2017). Paternal and maternal urinary phthalate metabolite concentrations and birth weight of singletons conceived by subfertile couples. Environment international107, 55–64. https://doi.org/10.1016/j.envint.2017.06.015

Mustieles, V., Williams, P. L., Fernandez, M. F., Mínguez-Alarcón, L., Ford, J. B., Calafat, A. M., Hauser, R., Messerlian, C., & Environment and Reproductive Health (EARTH) Study Team (2018). Maternal and paternal preconception exposure to bisphenols and size at birth. Human reproduction (Oxford, England)33(8), 1528–1537. https://doi.org/10.1093/humrep/dey234

Messerlian, C., Mustieles, V., Minguez-Alarcon, L., Ford, J. B., Calafat, A. M., Souter, I., Williams, P. L., Hauser, R., & Environment and Reproductive Health (EARTH) Study Team (2018). Preconception and prenatal urinary concentrations of phenols and birth size of singleton infants born to mothers and fathers from the Environment and Reproductive Health (EARTH) study. Environment international114, 60–68. https://doi.org/10.1016/j.envint.2018.02.017

Preconception health—the health of females and males in their reproductive years—is intrinsically linked to future generations’ health. Recent research suggests that certain maternal and paternal chemical exposures during critical windows of development prior to conception impact reproductive health and have transgenerational effects. Prenatal and early life exposures to certain endocrine disrupting chemicals (EDCs) have been linked to puberty at an earlier age, and trends over several decades in earlier pubertal onset in both males and females have been observed. (1) (2) (3) EDC exposures prior to conception have also been associated with low birth weight and preterm birth. (4) (5) Furthermore, preterm birth rates have increased over the past five years in the US, with Black women twice as likely to give birth before 37 weeks compared to White and Hispanic women. (3) The implications of these trends indicate the need to better educate medical professionals and individuals around the importance of health during this critical period prior to pregnancy.

EDCs are ubiquitous in our environment—found in food and food packaging material, water, air, personal care products, furniture, clothing, and more. Maternal and paternal preconception exposures to individual and mixtures of endocrine disrupting chemicals (EDCs) like phthalates, parabens, and phenols have been linked to multiple adverse reproductive health and birth effects including early onset puberty, reproductive cancers, low birth weight, and preterm birth. In the fourth webinar in our Generation Chemical series, Janet Hall, MD, MS, Kim Harley, PhD, Carmen Messerlian, PhD, MSc, and Yu Zhang, BA, discussed the latest science on preconception exposures and associated trends in reproductive health and development. They also discussed racial disparities in certain chemical exposures and important policy recommendations.

Association of phthalates, parabens and phenols in personal care products with pubertal timing in girls and boys

Onset of puberty in girls has been getting earlier over the past decades, putting girls at increased risk of mental health problems in adolescence and reproductive cancers later in life. There is some evidence that pubertal timing in boys may also be changing, but research is less clear. One hypothesis is that endocrine disrupting chemicals in consumer products, food, and homes may be partially responsible for this shift in pubertal timing. EDCs —including phthalates, parabens, and triclosan—are widely used in personal care products and have been shown to impact timing of puberty in laboratory animals. Dr. Kim Harley and colleagues investigated the impact of these chemicals on timing of puberty in boys and girls followed from before birth through adolescence as part of the CHAMACOS longitudinal cohort study. Dr. Harley presented data on children’s exposure to phthalates, parabens, and other phenols in utero and in early childhood and their associations with pubertal timing.  Larger implications and methods to reduce exposure were also be discussed.

Environmental Influences on Couples’ Reproductive Success: The Role of Phthalates, Phenols and their Mixtures on Adverse Perinatal Outcomes

The period of time before conception is a vulnerable window of disruption to gametogenesis, embryogenesis, and fetal growth and development, yet it remains highly overlooked, especially for men. In this webinar, Dr. Carmen Messerlian and Yu Zhang presented findings from recent work showing that maternal and paternal preconception exposure to phthalates, phenols, and their mixtures were associated with adverse perinatal outcomes and that both members of the couple contribute jointly. Importantly, findings suggest that paternal preconception exposures may play a similar or more important role than maternal preconception exposures on adverse birth outcomes. Results on birthweight and preterm birth using single-chemical analyses as well as mixture analyses were discussed. Clinical and policy translational research recommendations were also presented in brief.

Featured Speakers

Janet Hall, MD, is a Senior Investigator at NIH and Chair of the Clinical Research Branch and Clinical Director of the National Institute of Environmental Health Sciences. She completed her undergraduate, graduate, medical and Internal Medicine training at McMaster University in Ontario, Canada and her Fellowship in Endocrinology & Metabolism at Massachusetts General Hospital. Dr. Hall spent much of her professional life at MGH with consistent research funding from NIH and rising to the rank of Professor of Medicine at Harvard Medical School before taking up her current positions at NIH. She is an internationally known  clinician and clinical investigator with over 200 peer-reviewed publications as well as major chapters in the leading textbooks of medicine and reproductive endocrinology. Her research focuses on neuroendocrine and ovarian integration in control of the reproductive system in health and disease, including the effects of endocrine disrupting chemicals (EDCs) on the reproductive system. Dr. Hall is a member of the Association of American Physicians and is Past President of the Endocrine Society and of Women in Endocrinology. She has been Associate Editor of both the Journal of Endocrinology and MetabolismandEndocrine Reviews and is a recipient of the Sidney Ingbar Award for Distinguished Service to the Endocrine Society. She currently serves on the Endocrine Society’s Advisory Committee on EDCs.

Kim Harley, PhD, is a reproductive epidemiologist and a faculty member in Public Health at the University of California, Berkeley.  Her research focuses on endocrine disrupting chemicals and women’s health, including associations with fertility, birth outcomes, timing of puberty, and obesity.  She is the Associate Director of the CHAMACOS Study, a longitudinal cohort study examining environmental exposures to immigrant farmworker women and their children in California.  Dr. Harley is also the Principal Investigator of several youth empowerment projects that train young people to identify environmental justice problems in their communities and conduct public health research to address them – including the HERMOSA Study of young girls’ exposure to chemicals in make-up.  Her latest research project investigates chemicals of concern in cosmetics and personal care projects marketed towards minority women. She is also the principal investigator of an intervention to reduce women’s chemical exposures through their household cleaning products. Dr. Harley has published more than 100 peer-reviewed papers on the health effects and exposure patterns of phthalates, parabens, BPA, flame retardants, pesticides, and other endocrine disruptors in our homes and daily lives. 

Carmen Messerlian, PhD, MS, BS, is an assistant professor of environmental reproductive, perinatal, and pediatric epidemiology at Harvard T.H. Chan School of Public Health, and the director of the Scientific Early Life Environmental Health & Development (SEED) Program. Her research is focused on examining the extent to which environmental exposures affect a couple’s ability to achieve conception, maintain pregnancy, and deliver healthy offspring. Dr. Messerlian investigates paternal and maternal exposures to phthalates, phenols, PFAS, and other emerging chemicals and their mixtures on ovarian reserve, time to pregnancy, pregnancy loss, preterm birth, birth weight, placental parameters, and child development outcomes. She appliescutting-edge epidemiologic methods to generate evidence-based knowledge of the effects of environmental chemicals on fertility, pregnancy, and child health outcomes. Her ultimate goal is to use this evidence to inform clinical practice and improve health for mothers, fathers, and their children.

Yu Zhang is a doctoral student in environmental and reproductive epidemiology at Harvard T. H. Chan School of Public Health. She received her bachelor degree from Peking University in China. Her research under Dr. Carmen Messerlian’s mentorship aims to understand how endocrine disrupting chemicals, including phenols, phthalates, and polyfluoroalkyl substances influence perinatal outcomes, with a focus on identifying critical period of vulnerability and underlying pathways. She examines preconception chemical exposure in both parents in relation to pregnancy loss, preterm birth, and birth weight. She applies advanced statistical methods to study the joint effect of chemical mixtures on couple-based outcomes. She also explores environmental exposures during the prenatal window on adverse birth outcomes.

The “Generation Chemical” webinar series is brought to you in partnership with the Collaborative on Health and the Environment(CHE) and the University of California, San Francisco Program on Reproductive Health and the Environment (PRHE),the International Federation of Gynecology and Obstetrics(FIGO), Alliance of Nurses for Healthy Environments (ANHE), Endocrine Society, the International Federation of Fertility Societies (IFFS), and UCSF’s Environment Research and Translation for Health Center (EaRTH).

This webinar was moderated by Janet Hall, MD, MS, Clinical Director and Head of the Reproductive Physiology and Pathophysiology Group, NIEHS. It lasted for 70 minutes and was recorded for our call and webinar archive.