I asked Dr. Jay Gordon this questions awhile back, and he responded with a quick, “Definitely! The molecules are too big to pass through breastmilk!”
Here is a little more info from La Leche League International:
Tattoos are created by injecting ink into the dermal (second and third) layer of the skin. Tattooists use a hand-held electric machine that is fitted with solid needles coated in the ink. The needles enter the skin hundreds of times a minute to a depth of up to a few millimeters. The ink that is used in tattoos in the United States is subject to FDA regulation as cosmetics, but none are approved for injection under the skin. However, the ink molecules are too large to pass into breastmilk. –LLLI
Tattoos have the same risks for nursing and non-nursing women, mainly, localized infections, allergic reactions, keloids and dermatitis.
Going to a reputable tattoo artist is of the utmost importance, regardless of whether you are breastfeeding or not. If the artist does not take the standard sterility precautions you could be at risk for contracting:
- Viral hepatitis
So, it sounds like if you find a reputable artist who goes out of his or her way to take the correct precautions, tattooing when breastfeeding is absolutely a valid option.