If you’re ever planning to have kids, there’s a certain time you have to start rethinking all the things you’re putting into and on your body. Some chemicals in personal care products are no big deal for your adult, completely-developed body and brain. But a growing number of studies have found how these ingredients can impact a fetus as it develops. Sure, using natural products is always a good idea. But if it’s not something you’ve prioritized most of your life, you may need to make big changes when the time nears.

“In utero is the most critical time for chemical exposure,” Grace Lee, founder and CEO of pregnancy-safe beauty line Nine Naturals told us. “A growing number of studies have shown that common chemicals in everyday personal care products, such as shampoo, makeup and moisturizers, are associated with developmental and behavioral disorders, hormone disruption and cancer.”

According to the American College of Obstetricians and Gynecologists, exposure to environmental chemicals in the air, water and consumer products we use can cross the placenta, in some cases accumulating in the fetus and exposing the fetus to higher levels than even the mother.

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Prenatal exposure to chemicals is not only linked to negative health consequences for the baby, but some can also affect your reproductive health. You probably never thought your beauty products could affect your ability to get pregnant, did you? Two big culprits are BPA and triclosan, both of which have been shown in studies to be potential hormone disruptors.

So when should you start tweaking your habits for pregnancy? Lee recommends as early as possible, since many chemicals can build up in the body and take a little while to be flushed from your system completely. Perfect example: One 2012 study found that 99% of breast cancer patients being tested had parabens accumulated in their breast tissue. Researchers pointed out that this doesn’t necessarily mean parabens cause breast cancer, but the fact that almost all the women had parabens stored in their breast tissues is alarming, and warrants further research.

The other no-no ingredients you should avoid: phthalates, sulfates, petrochemicals, BPA, tricolsan, DEA, and any sort of synthetic fragrances or artificial preservatives. It’s also smart to avoid the peroxide in teeth whitening products — stick to using a whitening toothpaste instead, Dayna Salasche, MD, clinical instructor of obstetrics and gynecology at Northwestern University’s Feinberg School of Medicine in Chicago, told WedMD. In this case, it’s more about what we don’t know about the chemical’s affects — and when your developing baby’s health is at stake, erring on the side of caution is the way to go.

It may seem overwhelming, so we’re here to give you some guidance.

The biggest — and actually, very simple — thing you can do to make sure you’re using safe products is to become a label-reading tycoon. Just like you (hopefully) scan the nutrition information and ingredient list of food at the grocery store before you buy it, you should start doing the same with your products. It’s up to you to vet a brand and investigate the ingredients to make sure it’s truly safe, even when they claim to be natural. A single, agreed-upon definition of “natural” does not exist in the personal care industry, and many companies can make their claims however they like, whether or not they’re completely legit.

When checking out labels, it may be helpful to refer to Nine Naturals’ ingredients list, which was developed to explain each of their natural ingredients, what it does, and what it’s made of. It can help you familiarize yourself with names that may sound unnatural (like glyceryl stearate) that are actually completely OK — in this case, an emollient derived from coconuts. On the flipside, sometimes natural doesn’t always mean safe. Soy is natural, but there have also been studies showing soy may also have an impact on hormones.

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Cosmetic chemist Ni’Kita Wilson suggested to YouBeauty to choose only products that are directly pressed or extracted from botanical sources like trees, flowers and herbs. This could mean finding small-batch brands that are transparent about where each ingredient has come from, like S.W. Basics or Tata Harper (which just came out with a Redefining Body Balm that’s great for minimizing stretch marks throughout pregnancy).

You can also look for products that have a seal guaranteeing the ingredients are natural. Here’s a list of products certified as natural by the Natural Products Association — the seal means it’s made with at least 95% natural ingredients. Other product seals, like Natrue, BDIH and Cosmos (which includes the Ecocert and Soil Association seals), certify varying standards of natural and organic. But keep in mind that just because a product doesn’t have that seal doesn’t mean it’s not natural — getting certifications can be a rigorous, pricey process, so plenty of brands (especially smaller, more homegrown ones) won’t have any sort of seal.

To make the biggest impact with the least amount of effort, Lee recommends starting with a product you use most frequently, like shampoo. “With no major effort, expense or sacrifice, you’ve just eliminated one regular source of exposure,” she said.

And don’t beat yourself up about being perfect. “The average woman uses 12 beauty products a day – that’s 168 different ingredients,” Lee said. “If you are switching out a majority of the products you use regularly, great job! You are hitting a large portion of your exposures from beauty products.”

Lee has some experience herself in switching to natural products during pregnancy. In fact, it’s what prompted her to start Nine Naturals. “When I was pregnant with my first, I kept running into the same two problems in finding safe, natural beauty products: 1) Most products that claimed to be natural still contained harmful ingredients, and 2) Many natural products simply didn’t perform well; the shampoos didn’t lather well and the body products didn’t do much for our skin,” she explained. She decided that she would just have to make her own.

Luckily, her brand and a handful of others exist now, so your job is just to become a smart shopper — no product chemistry labs required.

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