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Safety of hair products during pregnancy
Angela Chua-Gocheco, MD, Pina Bozzo and Adrienne Einarson, RN
Several of my pregnant patients who are hairdressers have asked me if exposure to products they use is harmful to their unborn babies. They also want to know if their pregnant clients’ personal use of hair products should be of concern.
There is no evidence of teratogenic effects for pregnant women exposed to these products from occupational use (ie, hairdressing); however, it is recommended that pregnant hairdressers wear gloves to minimize exposure, work for no more than 35 hours per week, avoid standing for prolonged periods of time, and ensure that the salons where they work have adequate ventilation. Evidence suggests there is minimal systemic absorption of hair products, so personal use by pregnant women 3 to 4 times throughout pregnancy is not considered to be of concern.
Des patientes enceintes qui exercent le métier de coiffeuse mont demandé sil était dangereux pour leur enfant à naître quelles soient exposées aux produits des salons de coiffure. Elles voulaient aussi savoir si leurs clientes enceintes avaient des raisons de sinquiéter si elles utilisaient elles-mêmes ces produits capillaires.
Il ny a pas de données probantes faisant valoir des effets tératogènes causés par ces produits utilisés professionnellement (p. ex. par les coiffeuses) sur les femmes enceintes; par ailleurs, on recommande aux coiffeuses de porter des gants pendant la grossesse pour minimiser leur exposition aux produits, de ne pas travailler plus de 35 heures par semaine, déviter dêtre debout pendant des périodes prolongées et dassurer une ventilation adéquate dans le salon où elles travaillent. Les données probantes révèlent une absorption systémique minimale des produits capillaires et, par conséquent, lusage personnel par des femmes enceintes de 3 à 4 fois durant leur grossesse nest pas considéré comme un sujet de préoccupation.
Chemicals in hair products colour, straighten, relax, curl, and bleach hair. Hair dyes are often divided into 5 categories: gradual hair colouring, vegetable dyes, temporary dyes, semipermanent dyes, and permanent dyes. 1 The most common chemicals used in permanent hair colours are phenylenediamine, 3-aminophenol, resorcinol, toluene-2,5-diaminesulphate, sodium sulfite, oleic acid, sodium hydroxide, ammonium hydroxide, propylene glycol, and isopropyl alcohol. 2 The chemicals used in hair straighteners or relaxers, bleachers, and permanents include sodium hydroxide, guanidine hydroxide, ammonium thioglycolate, ammonium hydroxide, petroleum, and hydrogen peroxide. 3, 4
Some of the chemicals used in hair products have been reported to be carcinogenic 5; however, many of these chemicals have been eliminated from oxidative dye products since the early 1980s. There have been reports of hair products being associated with bladder cancer, non-Hodgkin lymphoma, multiple myeloma, acute leukemia, and neuroblastoma in offspring. However, these results have been inconsistent; most studies conducted on personal or occupational use of hair dyes showed no increased risk of cancer. 6-9
Exposure during pregnancy
Experimental animal studies showed risks of teratogenicity due to some of the chemicals found in hair products, namely phenylenediamine, 10 aminophenols, 11-12 and ethanolamine,13 when used in very high doses. Human studies, however, show that exposure to these chemicals from hair dyes or hair products results in very limited systemic absorption, unless there are burns or abscesses on the scalp. Therefore, these chemicals are unlikely to reach the placenta in substantial amounts to cause harm to the unborn fetus. 14-18
As hairdressers are exposed to chemicals that have been suggested to be teratogenic, embryotoxic, and carcinogenic, Labrèche et al attempted to measure the chemicals in the air at a number of hair salons. All chemicals measured were well below the threshold limits recommended by the American Conference of Governmental Industrial Hygienists. 19 Hueber-Becker et al found that plasma levels of an oxidative hair dye were below the limit of detection in 18 hairstylists who each performed 6 hair-colour jobs in 1 day. 20
A study by John et al, who examined the working conditions of pregnant women in beauty salons, found that the risk of spontaneous abortions did not increase with the number of hair-dye jobs performed per week. 21
Zhu et al compared 550 hairdressers with a nonexposed group and found no statistically significant differences in fetal loss, preterm birth, small for gestational age babies, congenital malformations, or achievement of developmental milestones among their children. 22 A Swedish study also did not find an increased rate of birth malformations among offspring of hairdressers when compared with those of a nonexposed group. 23 In a later study, the same group found neither an increased risk of spontaneous abortion nor fertility concerns among hairdressers. 24
A case-control study by Blackmore-Prince et al found no increased risk for preterm delivery or low birth weight in 525 pregnant black women exposed to chemicals used to straighten and curl hair. 4 Another case-control study by Rosenberg et al also did not find an association with preterm deliveries and use of hair relaxers during pregnancy in 5944 black women. 25
There are no studies on occasional use of hair products during pregnancy. However, we have calculated that using these products 3 to 4 times during pregnancy would not be a concern, as they have minimal systemic absorption and women are exposed to them every 6 to 8 weeks at most during pregnancy.
In view of these data, use of hair products is unlikely to cause adverse fetal effects. With occupational exposure of hairdressers, the evidence suggests minimal systemic exposure to hair products; however, it is recommended that hairdressers wear gloves to minimize exposure, work for less than 35 hours per week, and avoid standing for prolonged periods of time. For the average pregnant woman, receiving hair treatments 3 to 4 times during pregnancy does not appear to increase risk of adverse effects on the fetus.
- Bolduc C, Shapiro J. Hair care products: waving, straightening, conditioning, and coloring. Clin Dermatol 2001;19(4):431-6. [Medline]
- Van der Walle HB, Kanerva L, Elsner P, Wahlberg JE, Maibach HI, Hairdressers. Handbook of occupational dermatology. New York, NY: Springer; 2000.
- Wickett RR. Permanent waving and straightening of the hair. Cutis 1987;39(6):496-7. [Medline]
- Blackmore-Prince C, Harlow SD, Gargiullo P, Lee MA, Savitz DA. Chemical hair treatments and adverse pregnancy outcome among black women in central North Carolina. Am J Epidemiol 1999;149(8):712-6. [Abstract/Free Full Text]
- Ames BN, Kammen HO, Yamasaki E. Hair dyes are mutagenic: identification of a variety of mutagenic ingredients. Proc Natl Acad Sci U S A 1975;72(6):2423-7. [Abstract/Free Full Text]
- Takkouche B, Etminan M, Montes-Martínez A. Personal use of hair dyes and risk of cancer: a meta-analysis. JAMA 2005;293(20):2516-25. [CrossRef]
- Rosenberg L, Boggs DA, Adams-Campbell LL, Palmer JR. Hair relaxers not associated with breast cancer risk: evidence from the black women's health study. Cancer Epidemiol Biomarkers Prev 2007;16(5):1035-7. [Abstract/Free Full Text]
- Kelsh MA, Alexander DD, Kales RM, Buffler PA. Personal use of hair dyes and risk of bladder cancer: a meta-analysis of epidemiologic data. Cancer Causes Control 2008;19(6):549-58. Epub 2008 Feb 20. [Medline]
- Zhang Y, Sanjose SD, Bracci PM, Morton LM, Wang R, Brennan P, et al. Personal use of hair dye and the risk of certain subtypes of non-Hodgkin lymphoma. Am J Epidemiol 2008;167(11):1321-31. Epub 2008 Apr 11. [Abstract/Free Full Text]
- Hruby E, Paar R, Lippl K, Schwarzinger B, Hofer H. Teratologic studies with m-phenylenediamine on rats. Oesterr Forschungszent Seibersdorf 1981;(4132):1-36.
- Elder RL. Final report on the safety assessment of p-aminophenol, m-aminophenol, and o-aminophenol. Int J Toxicol 1988;7(3):279-333. DOI:10.3109/10915818809023134. [Abstract/Free Full Text]
- Spengler J, Osterburg I, Korte R. Teratogenic evaluation of p-toluenediamine sulfate, resorcinol, and p-aminophenol in rats and rabbits. Teratology 1986;33(2):31A.
- Mankes RF. Studies on the embryopathic effects of ethanolamine in Long-Evans rats: preferential embryopathy in pups contiguous with male siblings in utero. Teratog Carcinog Mutagen 1986;6(5):403-17. [Medline]
- Lademann J, Richter H, Jacobi U, Patzelt A, Hueber-Becker F, Ribaud C, et al. Human percutaneous absorption of a direct hair dye comparing in vitro and in vivo results: implications for safety assessment and animal testing. Food Chem Toxicol 2008;46(6):2214-23. Epub 2008 Feb 29. [Medline]
- Cosmetic Ingredient Review Expert Panel. Final report on the safety assessment of HC Yellow No. 5. Int J Toxicol 2007;26(Suppl_2):113-24. [Abstract/Free Full Text]
- Cosmetic Ingredient Review Expert Panel. Final report on the safety assessment of Basic Blue 99. Int J Toxicol 2007;26(Suppl 2):51-63. [Abstract/Free Full Text]
- Kraeling ME, Bronaugh RL, Jung CT. Absorption of lawsone through human skin. Cutan Ocu Toxicol 2007;26(1):45-56.
- Corbett JF, Molaro R. The century of hair colour. Glob Cos Ind 2001;169:22-9.
- Labrèche F, Forest J, Trottier M, Lalonde M, Simard R. Characterization of chemical exposures in hairdressing salons. Appl Occup Environ Hyg 2003;18(12):1014-21. [Medline]
- Hueber-Becker F, Nohynek GJ, Dufour EK, Meuling WJ, de Bie AT, Toutain H, et al. Occupational exposure of haidressers to [14C]-para-phenylenediamine-containing oxidative hair dyes: a mass balance study. Food Chem Toxicol 2007;45(1):160-9. Epub 2006 Aug 30. [Medline]
- John EM, Savitz DA, Shy CM. Spontaneous abortions among cosmetologists. Epidemiology 1994;5(2):147-55. [Medline]
- Zhu JL, Vestergaard M, Hjollund NH, Olsen J. Pregnancy outcomes among female hairdressers who participated in the Danish National Birth Cohort. Scand J Work Environ Health 2006;32(1):61-6. [Medline]
- Rylander L, Källén B. Reproductive outcomes among hairdressers. Scand J Work Environ Health 2005;31(3):212-7. [Medline]
- Axmon A, Rylander L, Lillienberg L, Albin M, Hagmar L. Fertility among female hairdressers. Scand J Work Environ Health 2006;32(1):51-60. [Medline]
- Rosenberg L, Wise LA, Palmer JR. Hair-relaxer use and risk of preterm birth among African-American women. Ethn Dis 2005;15(4):768-72. [Medline]