Hair treatments.(Drugs, Pregnancy, And Lactation)

Women often have questions and concerns about the safety of hair treatments during pregnancy. The limited available data have not indicated problems with teratogenicity or other adverse reproductive outcomes associated with either occupational or personal exposure to hair dyes, permanent solutions, or other treatments such as straighteners.

That was our conclusion in a review that a colleague and I wrote in 1989 (JAMA 262[20]:2925, 1989). Since then, more studies have been published on this topic, but they do not alter our earlier conclusion.

Still, it is reasonable to advise women planning pregnancy to avoid hair permanents or dyes during the first trimester because of the paucity of direct information on the risks.

But this statement should not be interpreted to suggest that a problem exists. This distinction is particularly important for those exposed to these agents before they knew they were pregnant. There certainly is no indication that beauticians should stop working during pregnancy.

In vitro studies have shown that some of the compounds in hair products are mutagenic, but most have not been associated with birth defects in animal teratogenicity studies.

What needs to be considered is that exposure to these products is brief when they are used on the hair, and the effect of far lower concentrations is not clear. Quite a few of these products were tested in animal teratogenic studies and no problems were detected. These products have never been studied in humans in any organized manner. The studies included rodent studies, which found that topical application of dye formulations was not associated with toxic or teratogenic effects.

Another study of pregnant rodents found that different dyes administered by gavage caused no "biologically significant changes or defects."