August 23, 2022 – Carmen Messerlian, assistant professor of environmental reproductive, perinatal, and pediatric epidemiology, studies how the world around us—everything from chemical exposures to trauma to climate change—can affect reproductive health and development. She directs Harvard T.H. Chan School of Public Health’s Scientific Early Life Environmental Health and Development Program (SEED). Here, she discusses her work.
Q: What got you interested in studying the factors that can impact human reproductive health and development?
A: My curiosity about human reproductive health and development was sparked more than 20 years ago while training and working as a nurse at the Montreal Children’s Hospital emergency room. My first patient was an eight-year-old girl who came into the ER very, very sick. We had to save her life. Later that day she was diagnosed with leukemia. I followed her progress in the oncology ward for months. I also worked in the in-patient child psychiatry unit where I cared for a young boy who by the age of nine had faced so much trauma he had to live in the hospital. He was my patient in the unit for an entire year! He was born on the streets of Montreal to a mother who was homeless and who had a drug addiction. As a newborn, he was addicted to cocaine and came into this world with a host of disadvantages that were magnified by early life trauma and experiences that caused severe behavioral and emotional issues.
These two children and their suffering stuck with me my entire life. A week doesn’t go by where I don’t think of these kids. Their stories and my experience caring for them and the thousands more like them, untold. This is what inspires and motivates me to strive to understand and investigate early life exposures and environments that can cause diseases in children and how we can prevent adverse outcomes. Everything that I do is about trying to understand when and how exposures in mothers and fathers before they conceive pregnancies, or when they are pregnant, impact their chances of getting pregnant, of having a healthy pregnancy, and of delivering a healthy baby who can live to their full potential. These are the questions we address in the SEED Program, which includes a scientific team of more than 25 people.
Q: Can you give a few examples of research you’re working on?
A: The exposures that I look at are not just the chemicals that we are exposed to from things like plastics and the built environment, or the air we breathe from the natural environment, but also the social environment. The environment, for me, is defined broadly to include the natural, built, and social environments we are exposed to across life. For example, my team and I are currently investigating how early life exposures to trauma, sexual abuse, or other forms of early stress can impact our reproductive health across life. It’s astonishing to realize our social environment, and what you experience as a child, is an exposure that can impact your chances of getting pregnant, carrying a baby to term, having a healthy postpartum experience, or having a healthy child.
Early life exposures can also impact your reproductive health as you age, through perimenopause and menopause and beyond for women, and also across life for men. In children and teenagers, exposures to certain chemicals, foods, social environments, or stress can affect the rate at which your body matures—they can either accelerate or delay pubertal progression. These changes can affect both fertility and overall health across the life course. In women, the number of years we menstruate can affect our brain, heart, and bone health. Environmental exposures can influence our menstrual cycles, our fertility potential, and the age at which we reach menopause. Factors in earlier life that impact age at menarche or that accelerate our reproductive aging process can result in changes to our fertility and the age at which women reach menopause. We also have some work showing that women who enter menopause earlier have more precipitous cognitive decline, their brains age differently, and they have increased risk for age-related diseases. These are some of the hypotheses we are investigating using observational epidemiologic designs coupled with genetic and epigenetic data.
We also have a new paper on the impact of climate change on reproductive health. Species on earth are being strained and stressed by climate change. It’s not just the pollution, droughts, storms, and wildfires that are having a devastating impact—it’s also that our evolutionary capacity for reproducing is being strained. The more hostile our environment is, the more difficult it is to have healthy offspring. In the SEED Program, we’re looking at how air pollution affects the risk of cerebral palsy, how climate factors like heat affect eggs and sperm, how climate conditions impact our ability to take care of our kids adequately. For instance, California has experienced severe drought and forest fires. Are you going to take your five-month-old baby out for a walk under those conditions? No. How does staying indoors impact your baby’s health and development? The pandemic was an example of how our environment and changes to the way society functions can have an enormous influence on our children’s health and their life course exposures.
Q: What are some recommendations for how people can protect themselves from dangerous exposures that may affect their ability to conceive, maintain a pregnancy, or have a healthy child?
A: Don’t use any products on your skin or in your home that have scent or color—products like cleaning supplies, detergents, dryer sheets, soaps, deodorants, face and body creams, or car deodorizers. Those products have phthalates and phenols in them. Phthalates have been shown to harm reproductive health and affect a baby’s brain, immune system, reproductive health, and development during pregnancy, and phenols have been linked with decreases in brain and heart health and immune function, adverse birth outcomes, and pregnancy loss. Even tiny steps can help. So instead of wearing cologne seven days a week, use it five days a week, or three and apply it to your clothing not skin. Swap out products with scent or color for products that are more environmentally friendly, more plant-based, and free of chemicals of concern. There are affordable choices that can help reduce your exposure. Small, incremental changes over time in your home, in your personal care products, and in your food can amount to important changes to your body’s overall exposure.
The other thing we can do is to focus on nutrition. If you can afford to buy organic foods some or all of the time, you can reduce your exposure to harmful pesticides. Eat more fresh fruits and vegetables, less processed foods, less meat, more plant-based proteins. Also, try to reduce the amount of takeout food or prepared foods you get in paper, plastic, or cardboard containers. Food packaging and food contact material are laden with PFAS chemicals. Don’t cook foods in what is called “microwaveable” plastic or any plastic. Use wood, glass, or metal in your kitchen instead. Water filtration is an important household strategy. The filtration is not perfect but it can reduce some of the more common and harmful contaminants.
I want to get this sort of information into people’s hands in a way that’s tangible and relatable. To help achieve this, my team has produced a series of educational prevention pamphlets for the public downloadable on our website. It can take decades for policy change at the federal and state levels to lower the amounts of harmful chemicals in the environment. In the meantime, I’m interested in bottom-up approaches. That’s where the power is—working with groups of future mothers and fathers, teenagers, fertility doctors who have access to patients trying to get pregnant, ob/gyns who are counseling people who just had a miscarriage, doctors working in pediatric and adolescent health—trying to educate them about harmful exposures in our environment. My focus isn’t about getting a high-impact paper. It’s about the impact of the paper. I want to be known as the “people’s professor.” I want my work to matter to the people I am trying to reach and I want to change the way we care for our reproductive health. We’re working on real-life problems that make a difference in the world.