This sheet is about exposure to hair treatments in pregnancy and while breastfeeding. This information is based on published research studies. It should not take the place of medical care and advice from your healthcare providers.
What are the different types of hair treatments?
Coloring, curling (permanents), bleaching, and straightening (relaxers) are types of hair treatments. For this fact sheet, hair coloring includes temporary, semi-permanent, and permanent dyes. Common chemicals used in hair dyes include hydrogen peroxide, ammonia, and alcohol.
Chemicals used in hair treatments might irritate the skin, nose, and throat. A strong smell does not mean that you have a high level of exposure. For hair curling or permanent waves, the most common chemicals used have been ammonium thioglycolate and ammonia. Hair bleaching products contain hydrogen peroxide. Hair straighteners (relaxers) use a variety of chemicals, such as ammonium thioglycolate or, in older preparations, sodium hydroxide.
Hair treatments are regulated as cosmetics by the U.S. Food and Drug Administration (FDA). FDA has the authority to order mandatory recalls and require adverse event reporting. However, cosmetics do not need FDA approval before they go to the market. Hair treatments that are not made in the United States (U.S.) might contain dangerous substances or contaminants, such as heavy metals, including lead, cadmium, nickel, arsenic, or mercury. In the U.S., the level of metals allowed in cosmetics is regulated.
Is hair coloring/dye absorbed through the skin?
The amount absorbed can depend on the health of the skin, the amount of active ingredients in the product, the area of skin exposed to the product, and how often it is used. Some hair treatments, such as highlights, lowlights, frosting, and streaking, apply the dye or color directly to the hair shaft without touching the skin. When these products are used as directed by the manufacturer, the amount of dye that is absorbed by unbroken, healthy skin of the scalp is small.
I get/perform hair treatments. Can they make it harder for me to get pregnant?
A report that summarized findings from 19 studies on reproductive outcomes among hairdressers and cosmetologists found a small increase in the time it took to get pregnant. Since then, two other studies have suggested that hair care products might be linked to trouble getting pregnant. One study looked at hair dye use in countries outside the U.S., and the other looked at hair straighteners.
Work settings and personal health and habits can differ among hairdressers and cosmetologists in these studies. For example, workplaces can differ in the types and mixtures of chemicals used, working conditions, ventilation, and working hours. That makes it difficult to know whether the job or other factors could make it harder to get pregnant.
Do getting/performing hair treatments increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. Studies in laboratory animals exposed to dyes at levels 100 times higher than normally used in humans did not suggest a greater chance of miscarriage.
Some hair straightening and smoothing treatments can contain formaldehyde or chemicals that release formaldehyde when heated. This can increase exposure to formaldehyde in people who provide these treatments, especially in workplaces with higher levels of exposure. Some studies of people who work around formaldehyde have suggested an increased chance of miscarriage.
Do getting/performing hair treatments increase the chance of birth defects?
Birth defects can happen in any pregnancy for different reasons. Out of all babies born each year, about 3 out of 100 (3%) will have a birth defect. We look at research studies to try to understand if an exposure, like hair treatments, might increase the chance of birth defects in a pregnancy. Getting or providing hair treatments as directed is not expected to greatly increase the chance of birth defects.
Do getting/performing hair treatments increase the chance of other pregnancy-related problems?
Some studies have suggested that working as a cosmetologist or hairdresser might increase the chance of preterm delivery (birth before 37 weeks of pregnancy) or having a baby who is smaller than expected (small for gestational age). One study suggested that regular use of hair oils later in pregnancy might be associated with preterm delivery. Another study suggested that weekly use of hair dye in a country outside the U.S. might increase the chance of stillbirth (loss of the baby after 22 weeks of pregnancy). Two studies have suggested that exposure to ingredients in some hair products, such as dye, during pregnancy might be linked to lower birth weight.
Work settings and personal health and habits can differ among hairdressers and cosmetologists in these studies. For example, workplaces can differ in the types and mixtures of chemicals used, working conditions, ventilation, and working hours. That makes it difficult to know whether the job or other factors could make it harder to get pregnant.
Does getting/performing hair treatments in pregnancy affect future behavior or learning for the child?
It is not known if getting or performing hair treatments during pregnancy can increase the chance of behavior or learning issues for the child. The limited information available on pregnancy outcomes among hairdressers and shop assistants has not shown an increased chance of learning or behavioral problems in their children.
I work as a cosmetologist/hairdresser. Is there anything I can do to reduce exposure at work?
All studies support the importance of proper working conditions. Working in a well-ventilated area, wearing protective gloves, washing hands after handling hair care products, taking frequent breaks, following product safety instructions, practicing safe handling and storage of hair care products, and avoiding eating or drinking in the workplace can help reduce chemical exposures.
MotherToBaby has a general fact sheet on workplace exposures and ways to reduce potential exposures at https://mothertobaby.org/fact-sheets/reproductive-hazards-workplace/. Your worksite should provide the manufacturer’s Safety Data Sheets (SDS) on all chemicals and proper personal protection for all parts of your job. Be certain to use them, even when not pregnant or breastfeeding. Working in well-ventilated areas and following recommended safety practices can help reduce exposure to chemicals from hair products.
If you perform hair treatments at home by yourself, it is important to follow all safety measures listed on the product label or instructions, work in a well-ventilated area, and wear the correct type of gloves.
Breastfeeding and hair treatments:
When used as directed on healthy, unbroken skin, it is unlikely that large amounts of hair care chemicals would get into breast milk because only small amounts would enter the blood of a person getting or providing hair treatments. Be sure to talk with your healthcare provider about all your breastfeeding questions.
If a man does preforms/gets hair treatments, can it affect fertility or increase the chance of birth defects?
It is not known if hair treatments could affect men’s fertility (ability to make healthy sperm) or increase the chance of birth defects. In general, exposures that fathers or sperm donors have are less likely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.
Please click here for references.
