Hair Coloring:

Permanent hair dye applied to the entire scalp can potentially be absorbed into the body.  According to the American Medical Association, it is recommended to stay away from hair coloring during pregnancy.  Dying your hair three times while you are pregnant is equivalent to smoking one to four cigarettes.  There are no well controlled studies to guarantee the safety of permanent hair dye usage in pregnancy; however, on the other hand, there is no evidence saying it can lead to birth defects either.  Consider color-enhancing glosses as a good alternative which also makes hair super shiny.  Ask your colorist about semi-permanent and demi-permanent dyes, which contain nearly no ammonia or peroxide.  To minimize exposure to salon chemicals, allow eight weeks or more between appointments and always request the first appointment of the day.

Hair Removal:

Waxing unwanted hair using a natural wax is safer than depilatories, which may cause an allergic reaction and can potentially seep into pores.  Waxing may be more painful when pregnant and some women may experience broken blood vessels from the procedure.  No studies exist to test the safety of laser hair removal and other laser/light-based treatments in pregnant women.  I would recommend to err on the side of caution and to avoid such procedures while pregnant.

Tanning:

Self-tanners only stain the skin's surface and are not absorbed into the body.  A second perk: provides a warm glow, without the damaging effects of UVA and UVB rays from the sun and tanning beds.

Hot Spa Treatments/Hot Tubs:

Hot tubs, hot baths, hot stone massages and body wraps can possibly cause miscarriages during the first trimester, by elevating the mother's own body temperature to simulate a high fever.  Fever during pregnancy can also put the unborn baby at risk for developing birth defects.

Manicures/Pedicures:

Artificial nails and some nail polishes contain chemicals that can potentially put the developing fetus' brain at risk.  In addition, inhalation of the chemicals and glues associated with artificial nails may be damaging.  Nails grow faster and are stronger during pregnancy, so acrylic nails and tips should be unnecessary.  If you decide to go to a salon, make sure they are reputable in cleanliness (i.e. sterilization of tools) and experienced in the care of pregnant women.  For pedicures, ask for cool water pedicures, since warm water may increase the body temperature.  Since massages are commonly associated with pedicures, limit the massages to below the ankle.  Certain pressure points located in the ankles may induce labor.  Also, deep tissue massages on the legs can be dangerous, due to the possibility of dislodging any blood clots.