These natural pathogens are all particularly dangerous for a developing fetus. Along with avoiding alcohol and tobacco, most of us willingly obey these new guidelines for the next nine months, no matter how much we enjoy French cheeses or Caesar salad (the traditional dressing includes raw egg, along with olive oil, lemon juice, garlic and anchovies). We cut back on caffeine and wash our vegetables diligently. It seems a small sacrifice for giving our child the best start at a healthy life.

But is that photocopied list from the doctor’s office the whole story? Modern medicine has excelled at identifying infectious bacteria and viruses, as well as publicizing well-understood preventable conditions such as Fetal Alcohol Syndrome. Unfortunately, that doctor’s list can’t possibly keep up with all the new food-processing additives and technologies — in many cases, the research is still in progress, but the food is already being sold and consumed while many continue to question its safety. In many cases, we don’t have decades of documented medical effects to draw upon — yet. Emerging research suggests prenatal hazards ranging from antibacterial hand soap to the fresh paint on the nursery walls, but here we will limit ourselves to what we choose to take into our bodies.

Some of the foods on this list are either highly processed convenience foods, or produced with reliance on dangerous chemicals with highly controversial effects. Others are the victims of the ever-increasing chemical burden on our soils and oceans. Especially where our children are concerned, it makes sense to rely on clean whole foods to provide both nourishment and peace of mind. Who wants to spend an entire pregnancy worrying? By keeping it simple and knowing where our food comes from, we can relax and treasure this miraculous time. We can form life-sustaining new habits to serve us well long after giving birth.

1. Microwave popcorn

Yes, it’s a tasty, convenient snack — a snap to produce at the office, promoted as a “wholesome” snack alternative, and a staple in many homes for movie night. Unfortunately, each microwavable bag is coated internally with fluorotelomers, a “miraculous” substance much loved in the packaging industry for its ability to repel liquid and oil. When exposed to high temperatures, fluorotelomers break down into PFOA, a compound transmitted directly to the fetus which has been linked to developmental problems, as well as cancer, liver disease, and thyroid disease. Although the Environmental Protection Agency “has not yet made a determination as to whether PFOA poses an unreasonable risk to the public”, they have ordered manufacturers to phase out PFOA by 2015. Coating with fluorotelomers continues to be acceptable common practice, confusingly.

We may not wish to wait for the final judgment to be delivered. A simple electric air-popper makes popcorn making almost as easy, and you get to choose what to put on it: we suggest real butter or olive oil rather than the questionable hydrogenated oil/artificial flavor blend standard on microwavable popcorn.

2. Rice and rice products

For the whole-foods movement, this one is a shocker. Rice, particularly brown rice, has been the unimpeachable staple of a wholesome diet for many decades. Its reputation has endured through trends ranging from macrobiotic to vegan to gluten-free; white rice is even accepted by some grain-free advocates as a “safe starch”. How could simple whole-grain rice be wrong? Unfortunately, it’s out of the hands of even the growers: water-grown rice sucks up everything in its soil, including potentially troubling levels of arsenic. Some “organic arsenic” is naturally occurring, but the more toxic inorganic arsenic is usually residue or runoff from unrelated industrial agriculture, such as cotton growing and chicken farming. Though some arsenic-laden insecticides have since been banned, these chemicals persist indefinitely in the soil, and arsenic’s water-soluble nature makes it easy for rice, in particular, to absorb.

You can continue to eat small amounts of rice by choosing carefully: California-grown white basmati has one of the lowest levels. Brown rice, sadly for many of us, is much higher in arsenic, which concentrates in the bran, which is stripped off during the refining process. Especially during pregnancy, limit your intake to one small serving (1/4 cup uncooked) of rice per week, and avoid processed rice products such as crackers, cereal, gluten-free baked goods, and rice “milks” — these contain rice from unknown sources and in some cases may be significantly higher in arsenic. If you enjoy whole grains, now is a great time to experiment with easy-to-cook low-arsenic alternatives such as quinoa, buckwheat, and millet — all of which are also gluten-free.

3. Hotdogs, bacon, and lunchmeat

Sliced deli meats are often on the “don’t” list because of listeria risk. If you cook them well, they say, it’s OK. The problem is that cooking may destroy listeria, but other hazardous compounds are unaffected: at high heat, they may even be increased.

Most processed meats include large quantities of nitrates, which are harmless in themselves, but can convert in your gut to nitrites. After absorption, these nitrites can either form N-nitrosamines, known carcinogens, or attach to hemaglobin to form methemoglobinemia, which impedes your blood’s ability to carry oxygen. Both risks sound unacceptable during pregnancy. Your fetus needs all the oxygen it can get. High-heat frying will significantly raise the quantity of carcinogens formed.

Interesting nitrate fact: they are present in many healthy vegetables, such as spinach, beets, and carrots. These veggies, however, also carry a host of antioxidants which stop nitrites from forming nitrosamines — and they bring many other benefits as well. Organic, field-grown vegetables typically have the lowest nitrate levels. For lower nitrite risk, eat only freshly-cooked veggies: try not to cook more than you can eat at that meal.

Your local natural food store probably stocks processed meats made with minimal or no hazardous chemicals. As a bonus, these are often made from animals raised in a happier environment with less antibiotics and hormones. Cook them gently but thoroughly, at low-to-medium temperatures, and you can enjoy these treats occasionally without worry.

4. Farmed salmon

The benefits of omega-3 consumption are well-known: in pregnancy, omega-3 promotes optimal brain development, and may support immune functioning and heart health as well. Salmon is a great source of this essential fat. Unfortunately, PCB (Polychlorinated biphenyls) levels in farmed salmon are an average of eight times higher than in wild fish. Some research suggests PCBs cause cancer, but even more conclusive is the evidence that women exposed to high levels of PCBs are more likely to have babies with neurological and developmental problems.

Choose wild salmon, or take a fish-oil supplement made from wild fish. In restaurants, ask about the source. At the market, if it says “Atlantic salmon”, it’s farmed, or if it doesn’t specify the variety — most wild salmon will specify sockeye, chinook, pink, coho, etc. Not only will buying farmed salmon expose your baby to questionable risks, it also supports an environmentally problematic industry which is putting wild fish and the welfare of our oceans at grave risk.

5. Non-organic apples (and other high-pesticide fruits)

Word has spread about the Environmental Working Group’s “Dirty Dozen”: the list has become a standard for shoppers hoping to minimize their pesticide exposure even if they can’t afford to buy 100% organic. The list (and it’s counterpart, the “Clean Fifteen”) is updated yearly, and it does change significantly. Currently the apple — that symbol of american health — is in the place of shame at the top of the list. But strawberries and grapes are not far behind, and even kitchen staples like celery and potatoes come out looking bad. European regulators have already banned several chemicals (including neonicotinoids, suspected of causing massive honeybee die-offs as well as disrupting human brain development) which are still widely used in the USA and many countries which export produce to North America. The American Academy of Pediatrics reports that prenatal and childhood pesticide exposure can cause “pediatric cancers, decreased cognitive function, and behavioral problems.” Consumption of some genetically modified foods https://www.ncbi.nlm.nih.gov/pubmed/21338670, which have been bred to tolerate higher levels of both pesticides and herbicides, have been found to increase levels of these toxins in pregnant women and fetuses.

Growing your own or supporting local organic farmers doesn’t just protect against pesticide exposure, it contributes to a movement dedicated to reclaim the integrity of our ecosystems and communities.

So go ahead and order the guacamole: only 1% of conventional avocados showed detectable pesticide residues. But the next time you find yourself balking at the higher price of a carton of organic berries or a crisp Fuji, remind yourself what you’re actually investing in. Choosing seasonal produce helps to keep costs down: in summer, buy a few crates of fresh, succulent organic peaches or apricots at a bulk discount, then make a project out of canning or dehydrating them for the winter months ahead. It’s a very modern phenomenon, after all, that we’ve grown accustomed to eating fresh strawberries in November. Unfortunately, in the glow of the produce aisle it’s easy to forget they might not taste like much, and the poisons they contain lessens their appeal.

6. Canned soup

Nearly all canned food contains an epoxy liner containing BPA, which is an endocrine-disruptor thought to cause reproductive, brain development, and behavioral problems in children. Research has suggested links to a long list of additional medical concerns, including a variety of cancers. Pregnant women are widely advised to avoid BPA — unfortunately, all canned goods pose a risk, but prepared canned foods such as soups and pastas have been found to have particularly high levels leached into food. In general, the more acidic the food, the more BPA will be dissolved into the liquid (canned tomatoes are an obvious, and ubiquitous, example). Other common sources for BPA exposure include reusing single-use plastics, storing food or drinks in old, scratched plastic, and handling BPA-coated cash-register receipts.

Eat fresh or frozen produce whenever you can; choose jarred products over canned. The jar lid will still likely be lined with BPA, but there is significantly less surface area in contact with your food. Avoid microwaving frozen food in its packaging, even if the directions say it’s safe. Use glass, stainless steel, or ceramic for storing and heating food — if you absolutely must use plastic, look for recycling codes #1, 2, 4, and 5.

7. Soy milk and tofu

The phytoestrogens in soy products have a mixed reputation: some say they can help in soothing the effects of menopause, while others claim they may trigger dangerous hormonal changes. Dr Claude Hughes, director of the Center for Women’s Health at Cedars-Sinai Medical Center, explains “These hormones influence the way the brain is organized, the way the reproductive organs and cells develop, even the way immune function develops. Therefore, if mom is eating something or has in her body fat something that can act like sex hormones, it is logical to wonder if that could change the baby’s development.” Studies of prenatal exposure in rats showed “masculinizing” effects on both male and female fetuses.

The long-term effects of excess phytoestrogens in the womb could include early puberty as well as various reproductive problems and hormone imbalances. Animal research suggests that prenatal phytoestrogen exposure can even increase adult breast cancer risk. It’s too soon to know for certain how soy consumption in utero and early childhood affects later disease risks, but early research suggests plenty of reason for caution. Although fermented soy products such as tempeh and miso are often recommended as more digestible and containing less of soy’s harmful phytic acid, in the case of phytoestrogens, soy is soy. Choose other beans and legumes instead for plant-based protein.

8. Anything fried in non-stick cookware

The rumors around non-stick cookware are often bewildering. Are we in danger if we use a metal utensil to stir the food, or if we cook in a pan with scratched coating? It turns out that the damage to the coating, though it compromises the performance of the pan, is not our biggest worry. The real danger is invisible. When non-stick coatings are heated above 500F, they release fumes which can quickly kill a pet bird. Like the proverbial canary in the coal mine, these birds are simply the quickest the show the effects of these toxic gases. Humans can develop flu-like symptoms, and the long-term health risks are still being studied. The coating is made of polytetrafluoroetheylene (PTFE), a perfluorinated chemical (PFC).

Nearly all Americans test positive for PFCs in our blood. PFCs belong to a family of chemicals associated with low birth weight and size, thyroid and liver problems, and a weakened immune system. It’s unfortunately all-too-easy to overheat a pan: it can happen in just 2-5 minutes on a normal burner. Switch to stainless steel or cast iron for the stovetop. If you’re on a budget, check thrift stores for good-quality used cookware. If you have no choice but to cook in non-stick, never heat the pan empty, use your range hood, and always use low-to-medium burner settings. To further avoid PFCs, stay away from new carpets, upholstered furniture, and water-repellent clothing.

9. Apex predator fish (ahi tuna, swordfish, shark, king mackerel)

Previous warnings about high mercury levels in fish caused widespread fear of all fish consumption. Mercury is a major toxin that can accumulate in tissue (all women of childbearing age are advised to avoid it), and may damage an unborn child’s nervous system. Many consumers, including pregnant women, dropped fish from their diet entirely to avoid contamination.

Unfortunately, not eating any fish may be as risky as eating too much of the wrong type: your developing baby requires the nutrition abundant in fish for optimal development, including DHA and Omega-3 fats. In light of these concerns, the FDA is revising its recommendations to make it clear that all pregnant women should eat 2-3 servings of fish a week. Focus on low-mercury, high omega-3 choices such as wild salmon, sardines, mussels, anchovies, and farmed trout (land-locked trout farming is widely regarded as sustainable due to low waste output). Luckily there are well-organized lists available that make a trip to the fish market stress-free. Tilefish from the Gulf of Mexico is the worst mercury offender. Even albacore tuna should be seriously limited: “light” tuna is generally regarded as a better choice. Most shellfish are low in mercury, as are most smaller, low-on-the-food-chain fish.

10. High fructose corn syrup

For most educated consumers, avoiding soda-pop, candy, and associated junk-food has been on the radar for decades. But new information throws fructose, specifically, more sharply into the spotlight. The quantities of fructose Americans now consume, mostly as high fructose corn syrup (HFCS), are unprecedented. This means we are in uncharted waters as far as our future health consequences. Studies on animals suggest high-dose fructose is bad news: this substance appears to weak havoc with metabolism. Results included increased gestational diabetes, low birth weight (associated with lower IQ and autism) and disrupted metabolic functioning in both mother and fetus. Gestational diabetes is no joke: all the mother’s excess blood glucose is passed on to the baby, who has to produce extra insulin to cope with it. If not well controlled, gestational diabetes can lead to a baby with an overactive pancreas, possible breathing problems, and excess fat which can make childbirth more difficult or dangerous. Seizures and stillbirth are the worst risks faced.

The jury is still out on whether prenatal exposure to HFCS increases later risk for obesity, diabetes, or other conditions; it is confirmed, however, that gestational diabetes increases these risks. Babies and young children continue to be extremely vulnerable to metabolic disturbances as their development progresses through crucial stages: if breastfeeding is not an option, examine infant formula ingredients with care: corn syrup is a common sweetener. Choose a lactose-sweetened formula instead.

11. Trans fats (Partially-hydrogenated oils)

As if you need another reason to avoid those notorious “trans fats”! Early research has suggested that exposing a fetus to excessive trans fats can have long-term consequences. Such exposure could actually alter the fatty acid composition of the brain, change how our bodies react to insulin, and affect appetite.
Eliminating trans fats means avoiding fast food, deep-fried items, margarine, many shelf-stable baked goods and dough products, and other processed supermarket food (microwave popcorn makes another appearance on this list). In addition to protecting your child, you’ll be saving yourself from a host of possible repercussions. Trans fats raise “bad” cholesterol while lowering the “good”, increasing your heart disease risk. Other possible associations include Alzheimer’s, cancers, diabetes, infertility, and depression. If the ingredients list is too long to read through at a glance, put it back on the shelf and move on. Find bakeries where they use only real butter or unhydrogenated oils. Ask restaurants if they can steam or sauté your entree in olive oil rather than throwing it in the deep fryer. Your digestion will thank you!

What to eat during pregnancy is a deeply personal choice, and with so much conflicting information out there, sometimes all we can do is trust our instincts. If you decide to make the occasional exception in the name of a celebration or strong craving, don’t be hard on yourself! Health is about long-term habits, not obsessive rule-following.

This list is offered not to give pregnant women more to worry about, but rather in the hope of providing encouragement and information to support choosing the wholesome diet many women hope to achieve. It’s a poignant fact that for many of us, doing it “for the baby” is easier than doing it for ourselves. If we can use that motivation to eat delicious fresh foods during pregnancy, our whole family might catch on and join in, creating a small, local wave of vibrant, sustainable food culture that carries us into the future. After you’ve done enough reading up on all those confusing “do’s and don’t’s”, put down the computer and eat — consciously and joyfully.