Getting your hair done during pregnancy is generally considered safe. The chemicals in hair dye and other salon products are absorbed through the skin in only trace amounts, far too little to reach the placenta in meaningful quantities. The American College of Obstetricians and Gynecologists states that hair dye is usually safe to use during pregnancy. That said, not all salon services carry the same level of risk, and a few precautions can reduce your exposure even further.
Why Hair Dye Absorbs So Little
Your skin is a surprisingly effective barrier. When hair dye sits on your scalp for 20 to 40 minutes, only minimal traces of its chemical ingredients cross into the bloodstream. This holds true as long as your scalp is healthy, without open sores, cuts, or abscesses that could allow more chemicals through. Because so little gets absorbed, the chemicals are unlikely to reach your developing baby in amounts large enough to cause harm.
A large Japanese birth cohort study that tracked over 104,000 pregnancies found no significant association between hair dye use during the first trimester and spontaneous miscarriage. The study did find a link between more-than-weekly occupational exposure to hair dye (the kind hairdressers experience daily, not occasional personal use) and stillbirth. For someone coloring their own hair three or four times over the course of a pregnancy, the research does not point to measurable risk.
Which Treatments Are Lowest Risk
Techniques like highlights, balayage, and foils are considered the safest options because the dye is painted onto strands of hair and wrapped in foil, keeping it off your scalp entirely. With no scalp contact, there is essentially no absorption pathway into your body.
Single-process color (where dye is applied root to tip, directly touching the scalp) still falls within the safe range for occasional use, but it does involve more skin contact. If you want extra peace of mind, ask your stylist to apply color slightly away from your roots or choose a technique that avoids the scalp altogether.
Bleaching also penetrates the skin to a small degree, but not enough that most doctors would consider it harmful. Semi-permanent and vegetable-based dyes are another lower-exposure option since they don’t contain the same harsh chemical precursors found in permanent formulas.
The One Treatment to Avoid
Keratin smoothing treatments (often marketed as “Brazilian blowouts”) are the notable exception. Many of these products contain or release formaldehyde when heated with a flat iron. Formaldehyde becomes a gas at high temperatures, and both the stylist and client breathe it in. The FDA has flagged these products specifically, noting reported reactions including headaches, dizziness, nausea, chest pain, wheezing, and eye irritation.
Formaldehyde is classified as a human carcinogen by the International Agency for Research on Cancer, and at air concentrations above 0.1 parts per million it can irritate the respiratory tract. Even in a well-ventilated salon, these treatments generate enough heat-released gas to be a concern. Pregnancy aside, the inhalation risk is real for anyone in the room. During pregnancy, when you’re trying to minimize unnecessary chemical exposure, skipping keratin straightening treatments is a straightforward call.
Timing: Why Many Stylists Suggest Waiting
You may hear the advice to wait until your second trimester before getting your hair colored. The reasoning is that the first 12 weeks of pregnancy are when your baby’s major organs are forming, and many women prefer to be extra cautious during this window. There is no strong clinical evidence that a single dye session in the first trimester causes harm, but because the existing safety data is limited rather than definitive, some providers recommend the second trimester as a reasonable precaution. By that point, the most sensitive period of organ development has passed.
Three to four color sessions spread across an entire pregnancy is the usage level that research has evaluated and found no cause for concern.
Practical Tips for Your Salon Visit
- Choose good ventilation. Sit near an open door or window, or make sure the salon’s exhaust system is running. Chemical fumes from dye, bleach, and other products in the salon are more of an exposure route than the dye on your head.
- Ask for highlights or balayage. Keeping dye off your scalp eliminates the absorption question entirely.
- Wear gloves if you color at home. This is standard advice for anyone, but especially useful during pregnancy since your hands have thinner skin that absorbs chemicals more readily.
- Don’t leave dye on longer than directed. Follow the recommended processing time to limit unnecessary contact.
- Skip the keratin treatment. If you want smoother hair, ask your stylist about heat-free conditioning options that don’t involve formaldehyde-releasing products.
- Take breaks. If you’re spending a long time in the salon, step outside briefly for fresh air, especially if the space feels stuffy or you notice strong chemical smells.
Pregnancy Sensitivity to Watch For
Pregnancy changes your body in ways that can affect your salon experience. Heightened sense of smell, common in the first trimester, may make chemical odors feel overwhelming even if they never bothered you before. Some women also experience increased skin sensitivity, which could make scalp irritation from dye more noticeable. Neither of these means the chemicals are more dangerous, but they can make the experience uncomfortable. If nausea is still an issue, the smell-heavy environment of a salon may be easier to handle later in pregnancy when morning sickness has eased.
Hormonal shifts can also change your hair’s texture and how it responds to color. Your stylist may notice that dye takes differently or that your hair holds curl or straightness in unexpected ways. This is temporary and resolves after delivery, but it’s worth mentioning to your stylist so they can adjust their approach.