When you’re pregnant, it makes sense that you’d want to do everything you can to be healthy. After all, you’re growing another human, and that’s a pretty big responsibility. But there’s a concept floating around that you should have a “nontoxic” pregnancy. Have you heard of this? Here’s the problem: It's not really a thing.

For starters, the idea that you should do things — like follow certain diets or consume certain drinks — to get rid of "toxins" in your body isn’t based on science. Toxins are things that you introduce into your body by inhaling, eating or absorbing, and that can be considered poisonous (think: snake venom). While there are plenty of products out there that claim to detoxify you, they’re kind of bogus; your body detoxifies you naturally. “If a body is functioning normally, it does a good job in efficiently detoxifying itself through the liver, kidneys and sweat glands,” says women’s health specialist Dr. Jennifer Wider.

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There are, however, some ingredients and chemicals that you should try to avoid when you’re pregnant. They’re not toxins, per se, but they are things that you'll want to steer clear of if you can. Certain chemicals could cross the placenta and harm your developing baby, Wider explains.

Here are the big baddies to look out for.

Lead

Lead, which can impair a child’s brain development, comes primarily from old paint or drinking water in some old houses, says Sonya Lunder, a senior analyst at the Environmental Working Group. There are at-home test kits for lead if you’re concerned about your tap water.

Arsenic

Arsenic, which is linked to poor brain development, can be found in tap water and some foods, such as rice, which is why Lunder recommends avoiding rice-based ingredients in processed foods such as rice flour or rice syrup. But rice itself can be a healthy staple, she says.

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Pesticides

Pesticides have been tied to neurological problems and birth defects in babies who were exposed in utero, Wider says. The best way to stay away from pesticides during your pregnancy is to avoid spraying them in your house, Lunder says. It’s also a good idea to strive to eat organic produce, which is grown without pesticides, whenever possible.

Phthalates

Unfortunately, these are widespread and often show up in personal care items, cosmetics, toys and nail polish, among other things. “They are endocrine disruptors and have been known to cause miscarriage and sterility in developing fetuses,” Wider says.

Triclosan

This ingredient is often in antibacterial soaps and has been linked to low birth weight and poor APGAR scores (APGAR is a method used to quickly assess the health of newborns), Wider says. That’s why it’s so important to read the labels on your soaps before using them.

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Certain popular skin care ingredients

Salicylic acid, retinol and tetracyclines are in many skin care products you should ideally avoid while pregnant. While over-the-counter topical salicylic acid products may be safe, prescription-strength and oral forms of it aren’t; they can cause an increased risk of intracranial bleeding in the baby, Wider says. She adds that retinol, a form of vitamin A, has been linked to birth defects when taken in high doses. And then there's tetracyclines, which can cause discoloration of the fetus' developing teeth if used by the pregnant mother in the second and third trimester, Wider explains.

That’s a lot to take in, and it’s hard to stay on top of all this. “Women sometimes get overwhelmed by the long ‘No’ list, so sometimes we emphasize the positives instead,” Lunder says. For example, there are plenty of things you can do to boost your body’s ability to fight off hazardous chemicals — Lunder recommends taking a prenatal vitamin, drinking plenty of filtered tap water, and eating a healthy diet with lots of fruits and vegetables.

Obviously, it’s tough to avoid everything that could potentially cause a problem. So just do your best, and you'll be fine. And once you've got pregnancy covered, we've got your back when the big day arrives.