There's very little information about the safety of skin dyes during pregnancy. Although the Food and Drug Administration has approved the inks and pigments used in tattoos for cosmetic use, they are not approved for injection into the skin, and the FDA does not regulate the tattoo process.
In general, it's prudent to avoid unnecessary chemical exposure during pregnancy. Chemicals from skin dyes can be absorbed through your skin and have the potential to reach your baby. Your baby is undergoing an intricate process of development and growth and should be protected from unnecessary exposures, especially during the earliest months of your pregnancy.
Another issue is that tattoos may cause local skin reactions including allergic reactions, scabbing and inflammation. Pregnancy is a time when many women have extra-sensitive skin and may react more strongly to a tattoo than at other times in life. On one occasion I had to hospitalize a pregnant woman for intravenous antibiotics after she developed a serious bacterial skin infection from a cosmetic procedure.
The fact that tattoos require needles means it is possible to acquire a blood-borne viral infection such as hepatitis B, hepatitis C or AIDS if rigorous safety precautions are not followed. If you obtain a tattoo at any time in your life, be sure to choose a licensed practitioner who always wears gloves and uses sterilized equipment. All needles should be new, disposable and designed for single use only. Dressings should be packaged, sterile and unopened. Dyes and inks should be sterile and unopened. These precautions won't prevent you from developing a local skin reaction, but they will avoid the danger of long-term infection from using shared or improperly cleaned instruments.
Because of the above concerns, I recommend that you wait to have your tattoo until well after your pregnancy is over. The most prudent advice is to postpone getting a tattoo or permanent makeup until you have completed breastfeeding.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.