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Hair Dye and Pregnancy: Is it a safe mix?
General Advice
Generally, pregnant women are advised to avoid any kind of
chemicals or fumes. The reason for this stems from concerns
about possible physical birth defects and/or genetic defects
induced in the fetus. Some chemicals are known to cause birth
defects when a woman is exposed to them while pregnant. The
chemical interferes in some way with the normal bio-chemical
reactions that take place in fetal development. For most
substances, we do not know exactly how teratogenetic (the
medical term for something that causes birth defects) they are.
Obviously, no one wants to try them on a group of pregnant women
and find out!
What the Studies Say
The methods we are left with do not give us clear answers. We
have to look at women who have children with one type of birth
defect and work backward in their medical histories to see if there
is a pattern in exposure. When a pattern is found, it is unclear
whether that chemical really caused the birth defects or whether
that exposure is somehow related to yet another chemical or the
woman's genetic background.
Women who dye their hair might be different from the average
woman in many ways. Is she more likely to be Caucasian? Maybe
a natural brunette? Then perhaps the ethnic backgrounds of brown
haired Caucasians has the tendency toward that birth defect. Do
women in different parts of the country dye their hair more? Do
urban women dye more than their rural counterparts? Then maybe
what we are seeing is the effects of geographic differences in
exposure to toxins. The bottom line is we don't know. Doctors err
on the side of caution and say "you had better avoid this, just in
case."
Questions about hair dye use in pregnancy were asked in women
who had kids with a rare kidney tumor called Wilms' tumor. No
association with hair dye was found. Interestingly enough, the
same study failed to find associations with a number of other
common substances (coffee, tea, smoking) that had been found in
previous studies. This points out another problem forming taboos
for pregnant women from this kind of methodology-one study sees
an association, the next doesn't.
In 1998, a study found that hair dye was associated with about a
3% greater chance of a specific type of heart defect. It did not
conclude that the hair dye caused the defect. In fact, it had the
lowest increase of all the factors they reported, including
pesticides, painting, cleaning solvents, and certain medications.
Even the guys got in the act. Paternal marijuana use was
associated with an increase in a different heart problem of 7.8%,
which was over twice as much as hair dye usage. Are women who
dye their hair more likely to be the partners of guys who smoke
pot?
In any case, a single study found a small, possible association
between hair dye and a birth defect.
What You Should Do
Since most studies have not been for the sole purpose of
determining the risks of using hair dye during pregnancy, it is
difficult to know for sure if hair dye is a risk. The studies that have
been conducted so far have indicated that it is unlikely that hair dye
is a risk factor in specific cases, but we do not know if it is an
across the board risk factor (such as smoking or drinking would
be). In most cases, especially in the case of pregnancy, one should
err on the side of caution, especially since no conclusive evidence
has been able to indicate whether or not hair dye is a risk during
pregnancy.
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