You can safely tweeze, wax, and shave new stray hair. Skin bleaching and hair removal creams are probably safe during pregnancy, but there has been insufficient research to clear them since they can be absorbed through the skin and their effects on the baby are unknown. Permanent hair-removal techniques, such as laser and electrolysis, are thought to be safe in pregnancy. Both techniques penetrate the skin no deeper than a few millimeters. Consult your doctor to see if this is okay.

Tretinoin belongs to a group of medications called retinoids that contain vitamin A and may be associated with birth defects. Studies have looked at the effects of this cream in pregnancy and have found that babies whose mothers used it, even in the first trimester, had no increase in birth defects. However doctors recommend avoiding tretinoin cream in pregnancy. Another similar medication, isotretinoin, which is taken orally, may increase the risk of birth defects and is therefore contraindicated in pregnancy.

Although the research into the safety of hair dyes if used in the first trimester may seem conflicting, the amount of chemicals used is small and it's unlikely that hair dyes cause harm. Also, if your hairdresser uses foil, the dye is kept off your skin.

Previously, women were encouraged to remove nail polish before surgery. One of the reasons was that the "pulse oximeter," a device attached to your finger to measure the oxygen in your blood during surgery, may give lower readings if placed over nail polish. However the device works as intended with nail polish or long nails if it's mounted sideways on a finger. Therefore there's no need to remove your polish.