Environmental Toxins and Fertility

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November 1, 2019

There’s been more awareness over the years about environmental toxins and their impact on our health. A recent study came out in Fertility and Sterility about their impact on fertility and pregnancy – and I’ve summed up the major points for you. 


When we think about mercury exposure, fish usually comes to mind. This is because mercury is a by-product of industrial processes like coal burning and waste incineration. Fish can absorb mercury from seawater and from the prey they eat. This means that big fish usually have more mercury than little fish (because they eat more little fish). And big fish also live longer, meaning more mercury accumulation. So, if you eat fish high mercury levels, this will put you at risk for mercury exposure. 

Pregnancy Risk 

Mercury can cross the placenta and accumulate in your fetus, leading to higher levels compared to yours. Low levels of mercury in pregnant women are associated with lower IQ scores in their children.  

What to think about

  • How often do you eat fish?
  • Do you use personal care products with mercury?
  • Do you use mercury thermometers?
  • Do you work with mercury?


Don’t be scared about fish because not all fish is bad and fish is great source of protein. That said, it’s important to be mindful about the type of fish you’re eating. 

High mercury fish include:

  • Fresh/frozen tuna
  • Shark
  • Swordfish
  • Marlin
  • Orange roughy
  • Escolar

Health Canada advises that if you’re pregnant, planning on becoming pregnant, or are breastfeeding you should limit consumption of these particular fish to 150g per month.

If you’re pregnant, planning to become pregnant, or are breastfeeding, canned albacore (white) tuna consumption may lead to mercury exposure. This is should be limited to 300g per week. However, this doesn’t apply to canned light tuna, which is relatively low in mercury.

Overall, this doesn’t mean you need to limit the amount of fish that you eat. Health Canada recommends to continue eating at least 150 grams (5 ounces) of cooked fish each week during pregnancy.

Fish that contain lower amounts of mercury are:

  • Salmon
  • Trout
  • Herring
  • Haddock
  • Canned light tuna
  • Pollock (Boston bluefish)
  • Sole
  • Flounder
  • Anchovy
  • Char
  • Hake
  • Mullet
  • Smelt
  • Atlantic mackerel
  • Lake white fish


Many years ago, lead was used in gas, paint, and pipes. If you live in an older home, you’re at risk for lead poisoning – especially if you’re remodelling and renovating your home. Lead can also be found in jewellery, make up products and toys. 

Pregnancy Risk 

If you’re pregnant, high lead levels are associated with pregnancy-related high blood pressure, preterm delivery, low birth weight, miscarriage, birth defects and abnormal placenta formation. It may also affect intellectual development in kids. 

Have you been exposed?

  • Are you living in a home build before 1978?
  • Are you renovating it?
  • Do you use imported pottery when cooking?


It can be hard to reduce exposure, especially if you’re living in a home built before the eighties. Not to mention, recommendations stay not to renovate – which isn’t always feasible!

There are some things you can do to avoid lead exposure though. Avoid using cosmetics made with lead (lipstick can be one of them, so you may want to switch up brands), and don’t cook with lead-glazed pottery.


This is a heavy metal used in rechargeable batteries, paint pigment, and in plastic production. It enters food through soil, and can be found in shellfish, organ meats, rice, wheat, leafy greens, potatoes, and celery root. Smokers and nonsmokers are exposed to cadium through tobacco smoke.

Fertility Risk

Cadium can accumulate in the ovaries and lead to a decline in progesterone and hCG production. Researchers have found that it can also affect IVF outcomes, as it can result in decreased fertilization and implantation. It also acts as an endocrine-disrupting chemical, and can mimic and inhibit estrogen and lead to abnormal hormone levels and irregular cycles.

In men, high cadium levels may affect sperm quality, decreased motility, and decreased testosterone levels.

Pregnancy Risk 

If you’ve been exposed to cadium, it can accumulate in the placenta and is associated with preterm delivery, and can be found in breastmilk. It also competes with essential metals like zinc and copper – which are needed for fetal growth and development.

Have you been exposed?

  • Do you eat organ meats?
  • Are you exposed to tobacco smoke?
  • Do you buy organic produce?


Because smoking can lead to an increased risk, if you haven’t considered quitting, now might be the time – for the benefit of both you and your partner.

If possible, buying organic rice and produce (especially if you eat some of the above quite often), and avoiding organ meats if you’re trying to get pregnant/are pregnant. See my notes about organic produce in the pesticides section.


In the US, over 1 BILLION pounds of pesticides are used yearly, and can persist in the environment for years – eventually contaminating our soil, food, water and air.

Fertility Risk

Studies show that women who ate more fruits and vegetables with high pesticide residues, had a greater risk of pregnancy loss than women who are low-pesticide residue fruits and vegetables.

Pregnancy Risk 

In the preconception period, pesticides may lead to intrauterine growth restriction and low birth weight.

Have you been exposed?

  • Do you use pesticides around your home or on your pets?
  • Do you buy organic produce?


If you can, choose organic when possible. This doesn’t mean that everything in your fridge and pantry need to be organic though.

Every year the Environmental Working Group comes out with a list of the foods that are highly contaminated with pesticides called the Dirty Dozen. Because choosing organic produce can be expensive, if you find yourself frequently eating any of the foods on the Dirty Dozen list, consider their organic counterpart. Grocery stores like Costco commonly sell organic produce for much cheaper than others. I usually pick up all my berries and leafy greens from there.

Also, there are foods that you don’t need to worry about being organic. These are called the Clean Fifteen.

One last note about choosing organic products. Not only is it important that a product says it’s organic, it should have a Canada Organic, EcoCert Canada or USDA Organic seal. If it doesn’t have any of those, it may not be truly organic.

Endocrine Disrupting Chemicals (EDCs)

These are chemicals that can block or mimic your body’s on hormones. The most common EDCs are:

  • Bisphenol A (BPA)
  • Phthalates
  • Polybrominated diethyl ethers (PBDEs)

All 3 have been found in food, personal care products, plastics and dust.

BPA is used in plastics, canned food liners, receipts. It can be found in plastic baby bottles, pacifiers, toys, and reusable food and drink containers. We are all exposed to BPA on a daily basis, and in the US, 93% of people have detectable levels of BPA in their urine.

Phthalates are used as plasticizers in personal, medical, and consumer care products. Urinary levels are higher in people who eat out, compared to cooking at home. Women with endometriosis have been show to have higher phthalate levels.

Polybrominated diethyl ethers are used in flame retardants on upholstered furniture, textiles, carpeting, and some electronics. Exposure can come from dust brought into your home from shoes and outerwear.

Fertility Risk

BPA has been shown to affect oocyte quality, implantation, embryo development and placenta formation. Higher levels were also associated with miscarriage. In women going through IVF, urinary BPA levels were associated with fewer eggs retrieved. In men, BPA was associated with decreased sperm quality.

Women undergoing IVF with higher phthalate levels had a lower number of retrieved eggs, lower pregnancy rates, and higher risk of early pregnancy loss before 20 weeks gestation. In men, phthalates can cause sperm damage, and is associated with abnormal sperm parameters like motility.

High levels of PBDEs are associated with pregnancy loss.

Pregnancy Risk 

In utero exposure to phthalates has been associated with delivery at an earlier gestational age.

Have you been exposed?

  • Have you purchased new curtains, rugs, and furniture with flame retardants?
  • Do you frequently clean the dust in your home?
  • Do you take off your outdoor shoes before walking through your home?


Consider reducing your use of plastic containers (for both food and drink) and reheating them. Switch to glass and stainless steel instead. If possible, consider cooking at home more often rather than eating out.

Avoid canned foods that have the number 7 stamped on the bottom. Choose personal care products that are fragrance free.

One of the recommendations for avoiding PBDEs is avoiding purchasing new furniture – but this is not feasible at times. You may want to open your windows when it’s comfortable to do so and let the air circulate. Don’t walk inside with your outdoor shoes, and wash your hands when you come in from outside.

Air Pollution

Air pollution is pretty hard to avoid considering it’s everywhere, in particular high traffic places.

Fertility Risk

Elevated air pollution during the preconception period was associated with a higher risk of pregnancy loss.

Pregnancy Risk 

Air pollution has been associated with spontaneous pregnancy loss, preterm delivery, low birth weight, and stillbirth.

Have you been exposed?

  • Do you live in a high traffic area?
  • Are there wildfires in your area?


If possible, avoid outdoor activities when the air quality is poor, use a HEPA filter inside your home to reduce chemicals from air pollution.

Next Steps

There’s a lot to unpack with this study, and it seems that no matter what we do, there’s an environmental toxin wherever we turn. From my perspective, it may be best to address what we can address, and try not to worry too much about things we have no control over. For instance, it doesn’t seem feasible to get rid of a 2 year old carpet, but I can make sure to air out my home and vacuum on a regular basis.

At the end of the day, evaluate your daily routine and see which small changes you can make. If your’e drinking out of plastic on a daily basis, buy a glass or stainless steel water bottle if you can. If you’re a strawberry lover, make sure they’re organic. Litter changes still count!


Segal, T., & Giudice, L. (2019). Before the beginning: environmental exposures and reproductive and obstetrical outcomes. Fertility And Sterility112(4), 613-621. doi: 10.1016/j.fertnstert.2019.08.001

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