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Exposure to Common Chemicals in First Trimester Linked to Lower IQ in Children, Especially Boys

MedicalResearch.com Interview with:
Eva Tanner, PhD, MPH, Postdoctoral Researcher
Department of Environmental Medicine and Public Health
Icahn School of Medicine at Mount Sinai

Carl-Gustaf Bornehag, PhD
Professor at Karlstad University

MedicalResearch.com: What is the background for this study?

Response: Most prior research on health risks from chemical exposure study one chemical at a time. However, we are exposed to a multitude of chemicals every day in the air we breathe, food and water we consume, and things we touch. This is supported by global biomonitoring data showing that humans in general have a high number of chemicals identified in their bodies, i.e., in blood, urine, breast milk, saliva, etc. Unfortunately, we don’t know how such single chemicals act in complicated mixtures and impact our health, or the health of future generations.

We conducted this study to help understand how prenatal exposure to mixtures of proven or suspected endocrine disrupting chemicals – found in common consumer products – during the earliest part of life may impact a child’s brain development and cognition in school age.

MedicalResearch.com: What are the main findings? 

Response: Exposure to a mixture of endocrine disrupting chemicals measured in mothers during the first trimester of pregnancy was related to lower IQ (WISC) scores in their children at seven years of age, and boys were disproportionately impacted. Chemicals we detected as harmful included bisphenols A and F, certain pesticides (a pyrethroid and chloropyrifos), phthalates, perfluoroalkyl substances, and triclosan.

MedicalResearch.com: What should readers take away from your report?

Response: We should question current chemical safety guidelines and regulations since they are based on a paradigm looking at one chemical at a time. Our results indicate that mixtures of chemicals found in common consumer products can be harmful to child brain development, even when individual chemical levels are low. 

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

Response: We need more research on how specific chemicals influence different areas of a child’s cognitive ability, such as verbal comprehension and reasoning ability. We are currently doing further work to understand how BPA and its replacement compounds may impact these different areas. Furthermore, it is important to find fruitful collaborations between population-based epidemiology and experimental toxicology in cell and animal models to learn more the underlying biology. With such new knowledge, we have to develop new approaches for risk assessment and regulation of combined exposure for chemicals in mixtures.  

We have no conflicts of interest. 


Eva M. Tanner, Maria Unenge Hallerbäck, Sverre Wikström, Christian Lindh, Hannu Kiviranta, Chris Gennings, Carl-Gustaf Bornehag. Early prenatal exposure to suspected endocrine disruptor mixtures is associated with lower IQ at age seven. Environment International, 2019; 105185 DOI: 10.1016/j.envint.2019.105185

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Last Updated on October 24, 2019 by Marie Benz MD FAAD