ECHO Study Suggests Air Pollution, Secondhand Smoke, Formaldehyde Exposure Affect Length of Time to Get Pregnant

Author(s): Eva Siegel, Linda Kahn, et al.

Who sponsored this study?

This research was supported by the Environmental influences on Child Health Outcomes (ECHO) program, the Office of the Director, the National Institutes of Health, with co-funding from the Office of Behavioral and Social Sciences Research (OBSSR).

What were the study results?

The strongest evidence points to an association between exposures to traffic-related air pollution, secondhand smoke, and a chemical called formaldehyde—a common workplace exposure in construction sites and nail salons—and longer time to pregnancy. Specifically, exposure to particulate matter and nitrogen oxide gases lowered couples’ chances of becoming pregnant. Traffic and the burning of other types of materials besides gas and diesel create particulate matter and nitrogen oxide gases. Volatile organic compounds, which are used in manufacturing processes, did not appear to affect time to pregnancy.

What was the study's impact?

This review suggests that certain chemicals in the air may lengthen the time it takes for couples to become pregnant. More research is needed to better understand how these chemicals affect reproductive health. To collect this information, future studies can provide participants with personal air monitors that can let researchers know about the quality of air participants are actually breathing instead of relying on imprecise data from outdoor monitors or participant recall.

The research team also pointed out that there are remaining questions about whether the air people breathe around the time of conception is what matters most or whether there are certain life stages, such as puberty, when being exposed to air pollution may be especially damaging. The ECHO-wide Cohort, which allows researchers to access information from a large and diverse population, can serve as an important resource for answering these questions.

Why was this study needed?

Previous studies have looked at how air pollution may affect how long it takes to become pregnant. Time to pregnancy is a measure used to estimate a couple’s ability to conceive and is commonly used to diagnose infertility. In this paper, the authors review past studies on air pollution to identify types of air pollutants—including pollution from traffic, chemicals in the workplace, and secondhand smoke—that might affect how long it takes to get pregnant.

Who was involved?

This review includes all papers published in English on this topic from January 1, 1990 to February 11, 2021. The analysis covered 33 articles, of which eight looked at outdoor air quality, six looked at secondhand smoke exposure, and 19 looked at air quality in the workplace.

What happened during the study?

The research team searched six leading science libraries and identified 33 human studies related to exposure to outdoor and indoor air pollutants and time to pregnancy. The team read each article, assigned it a score based on the quality of the study design, and created summary tables containing the most important findings of each study. They then compared the consistency of results between studies, especially among high-quality papers, about whether certain types of air pollution affected time to pregnancy.

What happens next?

This is the third review this team of authors has written on chemicals and time to pregnancy. Individual authors will continue to fill in the research gaps previously mentioned, including conducting studies where women will be wearing personal air monitors.

Where can I learn more?

Access the full journal article, titled “Indoor and outdoor air pollution and couple fecundability: a systematic review” in Human Reproduction Update.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Read the associated article.

Published July 27, 2022

Download this summary

ECHO Study Suggests Air Pollution, Secondhand Smoke, Formaldehyde Exposure Affect Length of Time to Get Pregnant

ECHO Researchers Report Higher Levels of Oxidative Stress among Socioeconomically Disadvantaged Pregnant Women

Posted on June 10, 2022April 2, 2025 by Jodi Snare

A collaborative research effort led by Stephanie Eick, PhD, MPH of Emory University’s Rollins School of Public Health and Rachel Morello-Frosch PhD, MPH of the University of California, Berkeley investigated the relationship between various biological, behavioral, and social factors and higher levels of oxidative stress in pregnant women, which is often associated with poor prenatal health outcomes. Pregnant participants who were 30+ years old and had a college degree had lower levels of oxidative stress. In contrast, levels of oxidative stress were higher among pregnant participants who were overweight or obese, or unmarried. Levels of oxidative stress biomarkers were also higher among pregnant participants who were current smokers or had less than a high school education.

This research, titled “Associations between social, biologic, and behavioral factors and biomarkers of oxidative stress during pregnancy: Findings from four ECHO cohorts,” is published in Science of the Total Environment.

To measure oxidative stress, the researchers collected urine samples from approximately 2,000 pregnant participants in the mainland United States and Puerto Rico who were enrolled in one of four ECHO cohorts. They measured the levels of oxidative stress biomarkers at up to three time points during pregnancy and calculated the association between biomarker levels and biological, behavioral, and social factors. Maternal age, pre-pregnancy body mass index, marital/partnered status, parity, and smoking status were included as biological and behavioral factors while race/ethnicity, maternal education, and stressful life events were considered social factors.

“This is the largest study to date to examine the relationship between biologic, social, and behavioral factors and oxidative stress during pregnancy,” said Dr. Eick. “Our results provide important clues into how social and economic inequalities lead to poor health in pregnant women.” This study may also inform future studies looking at risk factors for preterm birth.

As for ongoing research, the team is examining the impact of oxidative stress on adverse pregnancy outcomes, such as preterm birth.

Read the Research Summary.

ECHO Researchers Identify Effects of Mixed Metal Exposures on Fetal Growth

Posted on March 23, 2022December 8, 2023 by Jodi Snare

In a collaborative research effort led by Caitlin Howe, PhD and Margaret Karagas, PhD of Dartmouth College, researchers observed an inverse association between the metalloid antimony and birth weight for gestational age, suggesting that this understudied metalloid may harm fetal growth. Their study, titled “Prenatal metal(loid) mixtures and birth weight for gestational age: a pooled analysis of three cohorts participating in the ECHO Program” is published in Environment International.

The study included approximately 1,000 mother-newborn pairs in three geographically and demographically diverse ECHO cohorts:

The Maternal And Developmental Risks from Environmental and Social Stressors (MADRES) study, a predominantly lower-income Hispanic cohort in Los Angeles, California
The New Hampshire Birth Cohort Study (NHBCS), a primarily non-Hispanic white cohort in northern New England
The Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) study, a Hispanic cohort in northern Puerto Rico.

The team pooled data from these three cohorts, measured multiple metals in the mothers’ urine samples collected during pregnancy and evaluated the associations with birth weight for gestational age using a multipollutant analysis approach. In addition to the findings for antimony, the team reported that the effects of other metals (cobalt, mercury, nickel, tin) on birth weight for gestational age differed by cohort and/or infant sex. The mixture of metals together did not impact birth weight for gestational age. Cadmium and molybdenum individually were not associated with differences in birth weight for gestational age.

“Previous research on this topic has mainly focused on one metal at a time, but individuals are often exposed to multiple metals simultaneously, which may interact in complex ways to impact health,” said Howe.

This research highlights the need to identify major sources of antimony, which may differ depending on the population, such that interventions can be developed to reduce exposure to this toxic metalloid. In the future, the research team would also like to expand their analysis to additional ECHO cohorts and participants, investigate other biomarkers of metal and metalloid exposures, and identify windows in pregnancy when the developing fetus may be most susceptible to these exposures.

Read the research summary.

ECHO Research Explores the Relationship between Early Life and Puberty

Posted on February 4, 2022December 8, 2023 by Jodi Snare

Collaborative ECHO research led by Izzuddin M. Aris, PhD of Harvard University found that children who grew more quickly than their peers in the first five years of life were more likely to start puberty earlier. The study examined the importance of early life factors in puberty development and found that male children who gained weight or grew faster than their peers in the first five years of life were associated with entering puberty at a younger age. The researchers found similar results in female children but only among those with faster weight gains during early childhood (two to five years of age). The article, titled “Analysis of early life growth and age at pubertal onset in US children,” is published in JAMA Network Open.

To obtain these findings, the researchers gathered height and weight data from nearly 7,500 children in 36 ECHO cohorts and examined the following markers of puberty:

Age at which the child reached maximum growth due to puberty
Age at first period (in female children only)
Pubertal development score
Onset of pubic hair development

The team studied how weight gain, height, and body mass index at ages 0–0.5, 0.5–2, and 2–5 years were related to puberty later in childhood.

“Puberty is a key stage during child development,” explained Dr. Aris. “Having a better understanding of the early life factors related to puberty is important to develop intervention strategies to prevent earlier pubertal onset.” Previous studies in the US have linked earlier puberty onset to diseases later in life, such as type 2 diabetes.

Dr. Aris says follow-up studies will aim to identify puberty’s role in explaining the relationship between early life factors and longer-term chronic diseases.

Read the research summary.

ECHO Researcher Publishes Review on Epigenetic and Environmental Influences on Generational Health

Posted on July 15, 2021December 5, 2023 by Jodi Snare

Previous studies show that the environment may affect the health of multiple generations in one family. Environmental exposures and behaviors can change a person’s epigenetics, the markers and structural changes that direct how genes are read and understood. These markers and changes form a “molecular memory” can be passed down across generations. For example, if a pregnant woman is exposed to a chemical, her children’s and possibly grandchildren’s health may be impacted through epigenetic changes.

Knowing this, ECHO researcher Carrie Breton, ScD of the University of Southern California and her writing team gathered information from past studies to provide a review of existing epigenetic research and evaluate the potential role of epigenetics in the passing on of health risks to later generations. Breton served as lead author and was accompanied by other ECHO researchers, such as Rebecca Fry, PhD of the University of North Carolina at Chapel Hill; Alison Hipwell, PhD of the University of Pittsburgh; Cristiane Duarte, PhD of Columbia University; Linda Kahn, PhD of NYU Langone Health; Rachel Miller, MD of Icahn School of Medicine at Mount Sinai; and Joseph Braun, PhD of Brown University. Their research, titled “Exploring the evidence for epigenetic regulation of environmental influences on child health across generations” is now published in Communications Biology.

“While complex childhood disorders clearly have genetic components, it is increasingly clear that the environment can play a substantial role in affecting risk, even across generations. Our question was how much evidence exists to support epigenetic mechanisms as one route for conveying that risk,” said Breton.

To collect information, the writing team reviewed several studies on humans and animals investigating the role of epigenetics in multigenerational health. They used these studies to build a broad view of how environmental exposures and behaviors can have a lasting impact on the health and well-being of children for generations to come.

Research from this review found evidence in animals and humans that environmental exposures can affect health across multiple generations, potentially through altered epigenetics. One of the challenges of studying epigenetics in humans is untangling the complex interactions between epigenetic, genetic, and environmental factors associated with certain health outcomes. The scale of the ECHO Program makes it uniquely situated to address questions about environmental exposures across generations.

“By looking at many results together, scientists can find important patterns and form a better understanding of how the environment can affect the health of a mother, child, and grandchild,” said Fry.

Read the research summary.

ECHO Review Suggests Environmental Exposures Can Affect Health Outcomes Across Multiple Generations

<< Back to Research Summaries

ECHO Review Suggests Environmental Exposures Can Affect Health Outcomes Across Multiple Generations

Authors: Carrie Breton, Rebecca Fry, Alison Hipwell, Cristiane Duarte, Linda Kahn, and Joseph Braun

Who sponsored this study?

This research was supported by the Environmental influences on Child Health Outcomes (ECHO) program, Office of The Director, National Institutes of Health.

What were the study results?

The review found many studies in animals and humans that showed a connection between certain environments, chemicals, and behaviors and health risks across multiple generations. While epigenetics most likely plays a role in these changes, it is often difficult to separate epigenetic effects from other causes. The team also pointed out the need for more studies to tease out the complexity of these effects.

Footnote: Results reported here are for a research project. Other or future research may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What was the study's impact?

This review article brings together results from many studies into one paper, which is usually more powerful than results from a single study. By looking at many results together, scientists can find important patterns and gaps in epigenetics research. This paper will help scientists better understand how the environment can affect the health of a mother, child, and grandchild.

Why was this study needed?

Studies show that the environment may affect the health of many generations in one family. Some of this effect comes from epigenetics, changes in how your genes are read and understood. Your environment and actions can change your epigenetics, and those changes can be passed on to your children and grandchildren. For example, if a pregnant woman is around certain chemicals, her genes may carry a “molecular memory” of those chemicals that can be passed on through her children. The purpose of this study was to put together what is known about epigenetics to understand how environments, chemicals, and behaviors may affect the health of children for generations to come.

Who was involved?

This research looked at previous studies on humans and animals and summarized the information.

What happened during the study?

The team of experts read a lot of studies on this topic and worked together to write a summary of current knowledge.

What happens next?

The ECHO Program will keep collecting data on the health effects of environmental exposures on children. The scale of the ECHO Program makes it ideal for the study of the ongoing, generational effects of these exposures.

Where can I learn more?

Access the full journal article, titled “Exploring the evidence for epigenetic regulation of environmental influences on child health across generations” published in Communications Biology.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published: June 22, 2021

Access the associated article.

Download this summary

ECHO Review Suggests Environmental Exposures Can Affect Health Outcomes Across Multiple Generations

More Environmental Exposures Research

Do chemicals that break down slowly in the environment affect how long it takes to become pregnant?

Author(s): Linda Kahn, Alison Hipwell, Kim Harley, Pam Factor-Litvak, Michele Klein-Fedyshin, Christine Porucznik, Eva Siegel, Yeyi Zhu

A review of studies that look at whether exposure to common non-persistent chemicals in consumer products delays the time it takes to become pregnant

Author(s): Alison E. Hipwell, Linda G. Kahn, Pam Factor-Litvak, et al

Review of Prenatal Air Pollution Exposure and Brain Development

Author(s): Heather E. Volk, Frederica Perera, Joseph M. Braun, Samantha L. Kingsley, Kim Gray, Jessie Buckley, Jane E. Clougherty, Lisa A. Croen, Brenda Eskenazi, Megan Herting, Allan C. Just, Itai Kloog, Amy Margolis, Leslie A. McClure, Rachel Miller, Sarah Levine, Rosalind Wright

ECHO Review Finds Air Pollution May Be Associated with Child Brain Development, Behavior

<< Back to Research Summaries

ECHO Review Finds Air Pollution May Be Associated with Child Brain Development, Behavior

Author(s): Heather E. Volk, Frederica Perera, Joseph M. Braun, Samantha L. Kingsley, Kim Gray, Jessie Buckley, Jane E. Clougherty, Lisa A. Croen, Brenda Eskenazi, Megan Herting, Allan C. Just, Itai Kloog, Amy Margolis, Leslie A. McClure, Rachel Miller, Sarah Levine, Rosalind Wright

Who sponsored this study?

This research was supported by the Environmental influences on Child Health Outcomes (ECHO) Program, Office of The Director, National Institutes of Health.

What were the study results?

ECHO provides a unique opportunity to study how air pollution can affect children’s brain development and behavior in a large, diverse study population. It also has the ability to study pollutant exposures by geographic area, which has been a limitation in previous research.

What was the study's impact?

This study sets up the possibility of future work in ECHO on the effect of prenatal air pollution exposure on brain development in children.

Why was this study needed?

This study summarized information on different ways to measure prenatal air pollution exposure and what we know about how air pollution affects children’s behavior and brain development. It also helps create a plan for ECHO to study how being exposed to air pollution in the womb may affect children’s behavior.

Who was involved?

This paper uses summary data from ECHO to learn if there may be enough participants in the future to study how air pollution can affect children’s brain development and behavior.

What happened during the study?

Researchers reviewed earlier papers on air pollution and child development to summarize what those studies found. Then, they used that information to develop a plan that ECHO might use to fill gaps in that earlier work to advance children’s health.

What happens next?

Future studies will do the work described here – to examine air pollution exposure in ECHO participants by geographic area to determine how air pollution can affect the brain.

Where can I learn more?

Access the full journal article , titled “Prenatal air pollution exposure and neurodevelopment: A review and blueprint for a harmonized approach within ECHO.”

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published: May 2021

Download this summary

ECHO Review Finds Air Pollution May Be Associated with Child Brain Development, Behavior

Jessie Buckley: Estimating Effects of Exposure Mixtures on Child Health: Novel Methods for Solution-oriented ECHO Research

Estimating Effects of Exposure Mixtures on Child Health: Novel Methods for Solution-oriented ECHO Research

Speaker:

Jessie Buckley, PhD, MPH

Johns Hopkins Bloomberg School of Public Health

ECHO Data Analysis Center (DAC)

Speaker Bio: Jessie Buckley is an environmental and pediatric/perinatal epidemiologist, working on research to inform environmental policies targeted at improving children’s health. Her work looks at developmental origins of health and disease framework and focuses on determining effects of early life exposure to endocrine disrupting chemicals on child physical growth and development. Using molecular epidemiology and advanced statistical approaches, she has conducted several studies evaluating the role of environmental chemical exposures in the development of childhood obesity. She has also researched the utility of biomarkers of exposure to several classes of environmental chemicals that have widespread human exposure, including phthalates.

Topic: Interest in understanding the combined effects of multiple exposures (i.e., mixtures) on children’s health is rapidly increasing, with a related proliferation of methods for estimating these effects. In this talk, Jessie will demonstrate two useful approaches for estimating mixtures effects – Bayesian kernel machine regression and quantile g-computation – with an application to endocrine disrupting chemical mixtures and childhood bone health. In addition, Jessie will introduce a novel statistical framework to advance solution-oriented mixtures research in ECHO by more directly informing practices, programs, and policies to improve children’s health.

Date: Wednesday, June 10, 1 to 2pm

Slides

Emily Oken: Using Cohort Studies to Understand Joint Effects of the Environment and Lifestyle on Health

Using Cohort Studies to Understand Joint Effects of the Environment and Lifestyle on Health

Speaker:

Emily Oken

Department of Population Medicine at Harvard Pilgrim Health Care Inc

Speaker Bio: Dr. Oken was trained in internal medicine and pediatrics and is currently a Professor in the Department of Population Medicine at Harvard Medical School and the Harvard Pilgrim Health Care Institute, and in the Department of Nutrition at the Harvard School of Public Health. Dr. Oken Directs the Division of Chronic Disease Research Across the Lifecourse within the Department of Population Medicine. Her research focuses on the influences of nutrition and other environmental factors during pregnancy and early childhood on pregnancy outcomes as well as long-term maternal and child health, especially cardiometabolic health, cognitive development, asthma, and atopy. Since 2016 she has led Project Viva, a pre-birth cohort study that has followed pregnant women and their children since 1999. Project Viva is currently conducting in follow-up visits with teens aged 17-19 and their moms. The team is doing a fantastic job weathering the challenges of transition to remote data collection.

Date: Wednesday, May 13, 1 to 2pm

Slides