Is it safe to use hair dyes during pregnancy? An uptade

Possible adverse impacts such as congenital malformations and childhood cancers of fetuses that may be caused by hair dye use during pregnancy have been debated for long years. Ames et al. found in 1975 for the first time that some hair dye contents created mutagenic impact on Salmonella typhimurium mutant Ta 1538 strain. Also, in many studies performed in these years, it was shown that chromosome and chromatid aberrations occurred in the mammalian cell culture exposed to hair dyes. Teratology studies carried out on the rats followed these studies in 1976 and 1977. The study titled as “Teratology and percutaneous toxicity studies on hair dyes” was conducted in 1976, and the study titled as “Dominant lethal mutagenicity study on hair dyes” was conducted in 1977. In vivo effects of hair dyes which were presented to be active mutagenically by in vitro tests were investigated in these studies. In the first study, 12 different hair dyes were applied to 12 white New Zealand rabbits for investigating the systemic toxicity of dyes and to 20 pregnant Charles River CD rats for investigating teratological effects on 1, 4, 7, 10, 13, 16 and 19 days of gestation. Hair dyes were applied topically 2 times a week for 13 weeks as described. Three of hair dyes were applied directly and other 9 of them were applied in the rate of 1:1 as usual by mixing with 6% hydrogen peroxide just before the use. In the teratology study, it was observed that a no change occurred in any significant soft tissue or skeletal system. In the percutaneous toxicity study, 25 tissue samples taken from each subject were analyzed and no histomorphological change was observed. Also urine samples were analyzed and no staining was observed in the urine. In the dominant lethal mutagenity study, 11 different types of hair dye were applied intraperitoneally to male Charles River CD rats 3 times a week for 8 weeks in 20 mg/kg doses. Then, within 2 weeks, they were copulated with female rats. At the end of this study, no increase was seen in fetal loss after implantation. These studies were followed by many other studies carried out on animals. In the study of Picciano et al. carried out in 1983 and 1984, analyzed 4-chlororesorcinol, m-phenylenediamine, pyrogallol, 6-chloro-4-nitro2-aminophenol, o-chloro-paraphenylen-diamine and N-phenyl-paraphenylen-diamine were analyzed teratologically and no embryotoxic/fetal toxic impact was found. The dose and frequency of hair dye applied in these studies are incredibly higher than the dose of hair dye applied in human topically once a month. However, based on the animal studies, it may be an assertive approach to a degree claiming that hair dyes have no teratogenic impact in human pregnancy. Prospectively investigating the potential teratogenic impact of hair dyes on human may cause some ethic problems. Therefore, in order to investigate the fetal impacts of exposure to hair dye, case-controlled retrospective studies based on interview method were conducted. In order to shed some light on this matter, reproductive results of hairdressers were analyzed as the profession group which expose to the hair dyes most. In 2002, Rylander et