Well, I did a quick search and found something on chemical hair dyes (it may be somewhat relevant since relaxers contain chemicals):
http://www.babycenter.com/expert/pregnancy/pregnancybeauty/3273.html
"Over the years, people have conducted animal studies trying to shed light on this matter. Some, but not all, studies have shown a few of the chemical compounds in hair dyes to be teratogenic (meaning they can cause birth defects). However, in many cases, the animals were exposed to extremely high doses of these chemicals, doses that far exceed the amount a woman would receive from coloring her hair every month or two. Clearly, the chemicals in both permanent and semi-permanent hair dyes are not highly toxic. However, no one knows for sure whether low-level exposures are risky.
The
Organization of Teratology Information Services, which provides information on potential reproductive risks, says that although the data are limited, coloring your hair during pregnancy is probably safe. They point out that these chemicals have been around a long time and no research shows they cause defects in newborns. Plus, very little of the chemical is actually absorbed into your system."
However, if I were you, I'd go straight to my doctor and ask him or her. Better to be safe than sorry.
