Medically Reviewed by:
Ivy Cheah, Senior Dietitian – Diabetes Educator certification by the International Diabetes Federation, Gleneagles Hospital Penang
Hair dye is one of the most popular forms of cosmetics that women may use. They work by changing the natural hair colour from one shade to another.
It is no secret that many commercial hair dyes contain a plethora of chemicals.
These are not only harsh to the skin but may also pose significant health risks, especially for expectant mums.
The topic of hair dye safety during pregnancy is a bit of a mixed bag.
While some studies have suggested that the chemicals in hair dye could potentially pose risks to the developing foetus, some of the evidence is not conclusive.
So, here’s what you need to know about pregnancy and hair dyes.
What Hair Is Dye Made Out Of
Almost all commercial hair dyes are formulated from chemicals.
The most common ones include ammonia, hydrogen peroxide, and of course synthetic pigments.
However, hair dyes also contain a variety of other compounds and substances. Each with a different purpose such as prolonging shelf life and conditioning the hair follicles.
Oxidative or permanent hair dyes work by stripping the original hair off its natural colour and replacing it with a new shade.
Nonoxidative or semi permanent hair dyes simply settle on the original hair without stripping it, offering a more subtle colour change.
Some of these chemicals, especially ones contained in permanent hair dyes, are often harsh.
They can seep into the skin and the scalp, causing irritation, dryness and other side effects.
International standards of safety have set controls over the minimum amount of these chemicals allowed in hair dye products.
However, continued use and exposure tends to have a cumulative effect.
What Chemicals In Hair Dyes You Should Watch Out For
There are several chemicals that may be safety concerns, whether you’re pregnant or not.
Some of these chemicals, like the fillers and the antioxidants, are seemingly harmless.
They help protect and reduce damage to the hair as a result of the chemical pigments.
Others are not so innocent; they can leave long-lasting damage on your hair and skin with repeated use.
Here’s a list of some of the common generic ingredients and chemicals used in the making of commercial hair dyes:
- Synthetic dyes: These are the chemicals responsible for the actual colour change in the hair. These include para-phenylenediamine (PPD), para-toluenediamine (PTD), and p-aminophenol.
- Oxidising agent: This is the chemical that helps activate the primary dye components and facilitates the colour development process. Common developers include hydrogen peroxide.
- Alkalising agent: Often included in hair dyes to adjust the pH level of the product. E.g., ammonia
- Conditioners and moisturisers: Many hair dyes contain ingredients to help condition and moisturise the hair during the colouring process and afterward.
- Preservatives and stabilisers: To ensure the stability and shelf life of the product. E.g., formaldehyde and phthalates
- Fragrances: Fragrances are added to hair dyes to mask any unpleasant chemical odours and to provide a pleasant scent.
- Thickeners and emulsifiers: These chemicals help give the hair dye its desired texture and consistency. E.g., alkylphenols ethoxylates
- Antioxidants: Some hair dyes contain antioxidants to help prevent colour fading and protect the hair from damage.
There are possibly hundreds of other chemicals that you need to be aware of, but it may be impossible to list them all here.
The ones that you should watch out for, however, are what scientists call ‘Endocrine Disrupting Chemicals’.
What Are Some Concerns About the Safety of Hair Dyes
For years, scientists have expressed concerns over the safety of chemical hair dyes.
Especially in regards to their use of toxic and possibly carcinogenic ingredients.
The concern primarily revolves around the absorption of these ingredients through the scalp and skin.
In particular, a class of chemicals called Endocrine Disrupting Chemicals (EDCs) as previously mentioned.
These are substances that interfere with the body’s endocrine (hormone) system, potentially leading to adverse developmental, reproductive, neurological, and immune effects.
While not all hair dye ingredients are necessarily EDCs, some chemicals commonly found in them may still result in endocrine disruption.
These include the ones mentioned before: PPD, formaldehyde, alkylphenols and phthalates.
Surfactants like alkylphenol ethoxylates can break down into alkylphenols, which have been identified as EDCs and are known to mimic estrogen in the body.
Certain phthalates, such as dibutyl phthalate (DBP) and diethylhexyl phthalate (DEHP), have been linked to endocrine disruption and reproductive toxicity.
Formaldehyde has been classified as a known human carcinogen by several health agencies, and it may also have endocrine-disrupting properties.
Moreover, the list of chemicals mentioned earlier have been associated with a variety of toxic and carcinogenic side effects.
These include skin irritation, dermatitis, hair loss, contact allergy, reproductive toxicity and many others.
Those who get their hair dyed every now and again may not be at risk, but if you are a habitual hair dyer, then these risks may be greater.
The fumes from these chemicals can also be dangerous. So if you are a colourist who works in a salon, the risk of hair dyes is still there (even if you don’t use the hair dyes on yourself).
However, it’s important to remember that these health risks are highest only among those who are already sensitive to the chemicals or have been exposed to them for a long period of time.
Many healthcare providers advise caution when using hair dyes during pregnancy, especially during the first trimester when the baby’s organs are developing rapidly.
Is Hair Dye Dangerous for Pregnant Mums?
The question of whether hair dye is dangerous or safe for pregnant mums is a difficult one to answer.
One study found that mothers who got their hair dyed 3 to 4 times during pregnancy did not experience any adverse effects; nor did their babies. The caveat being that these mothers got hair dye treatments between 6 to 8 weeks apart.
Meanwhile, another study found that continued exposure of hair dyes during pregnancy may be correlated with cancer in the unborn babies.
The most important thing to note is that there are hundreds of hair dye brands. Each with their own formulations and measurements.
So, it is hard to pinpoint exactly if one product is safer than another without more studies.
However, here are some of the known risks of using hair dyes for pregnant mums. We do know that several chemicals are responsible for the negative side effects on pregnancy.
Para-phenylenediamine (PPD), for example, is the most common allergen found in hair dye that’s been known to cause contact dermatitis.
Other adverse effects can include pigmentary changes, hair loss, skin malignancies and autoimmune disorders.
So, pregnant mums would do well to avoid these chemicals by reading the ingredients on the product before purchasing.
Alternatively, if going for a professional hair dye, mums should ask if their hair dyes contain any of the problem chemicals mentioned above.
On the flip side, we must also talk about pregnant mums who work in hair salons. They have the most secondhand exposure to the chemicals in hair dyes than mums who go in for a one-off treatment every few months.
Those who wish to be mothers as well should try to avoid using commercial hair dyes before they conceive a child.
In terms of those who work in salons as colourists, experts recommend wearing gloves and other protective equipment to reduce exposure.
Is Hair Dye Dangerous for Unborn Babies?
Even if the chemicals in hair dyes do not pose any risks to pregnant mothers themselves, the same cannot be said for their unborn babies.
One study found that using hair dye before or during pregnancy, or while breastfeeding, can increase the risk of certain cancers in children.
Hair dyes contain chemicals that can disrupt hormones in the body, which can be harmful to babies.
Hair dyes also increase the risk of allergic rhinitis and asthma in children born to mothers who use hair dyes extensively during pregnancy.
There is also some small chance of stillbirth.
However, it is important to understand that these studies may not have all the facts.
That said, it is still better to be safe.
So, avoid or reduce the use of hair dyes while you’re pregnant or if you’re thinking of getting pregnant.
What Mums Can Do Instead of Using Chemical Hair Dyes
Pregnant mums who wish to dye their hair can opt for natural or vegetable-based hair dyes such as henna.
Granted, this may not come in as many options and shades as you may like; but it’s the safer option.
There are many recent advancements in natural hair colour.
These products use pigments and dyes extracted from plants and botanical sources. Some examples include quinones, tannins, flavonoids, indigo, curcuminoids and carotenoids.
These all come from plants and herbs that you may be familiar with such as pomegranate, turmeric, birch bark and saffron.
It’s important to remember that even with the strongest plant dyes, you may still not be able to get the kind of results that commercial chemical-based ones can give you.
Plant-based hair dyes may not be as vibrant as chemical-based ones nor will they last very long.
However, just because many of these store-bought natural hair dyes contain plant extracts doesn’t mean they are free of chemicals either.
They may still contain preservatives, developers and fillers to maintain the colour and shelf life of the product.
That said, they are still safer than commercial versions that contain large amounts of ammonia and hydrogen peroxide.
Hair Dye Safety While Pregnant
There is both compelling and inconclusive evidence on the dangers of hair dyes for pregnant women.
Many individual chemicals in these products can be both toxic and carcinogenic to some extent.
However, the amount absorbed through the skin during the dyeing process may be too small to cause harm.
To err on the side of caution, some women choose to avoid hair dye during pregnancy.
But you can still opt for safer alternatives like vegetable-based dyes or highlights that don’t touch the scalp.
If you’re considering dyeing your hair during pregnancy, it’s best to consult with your healthcare provider who would know best. This ensures personalised advice for both you and your baby’s safety.
Disclaimer: The information provided in this article is for informational purposes only and should not be considered as medical advice from Motherhood. For any health-related concerns, it is advisable to consult with a qualified healthcare professional or medical practitioner.
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